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Lee H, Im S, Lee C, Lee H, Chu SW, Ho AHP, Kim D. Probing Temperature-Induced Plasmonic Nonlinearity: Unveiling Opto-Thermal Effects on Light Absorption and Near-Field Enhancement. Nano Lett 2024; 24:3598-3605. [PMID: 38407029 DOI: 10.1021/acs.nanolett.3c04420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Precise measurement and control of local heating in plasmonic nanostructures are vital for diverse nanophotonic devices. Despite significant efforts, challenges in understanding temperature-induced plasmonic nonlinearity persist, particularly in light absorption and near-field enhancement due to the absence of suitable measurement techniques. This study presents an approach allowing simultaneous measurements of light absorption and near-field enhancement through angle-resolved near-field scanning optical microscopy with iterative opto-thermal analysis. We revealed gold thin films exhibit sublinear nonlinearity in near-field enhancement due to nonlinear opto-thermal effects, while light absorption shows both sublinear and superlinear behaviors at varying thicknesses. These observations align with predictions from a simple harmonic oscillation model, in which changes in damping parameters affect light absorption and field enhancement differently. The sensitivity of our method was experimentally examined by measuring the opto-thermal responses of three-dimensional nanostructure arrays. Our findings have direct implications for advancing plasmonic applications, including photocatalysis, photovoltaics, photothermal effects, and surface-enhanced Raman spectroscopy.
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Affiliation(s)
- Hongki Lee
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea 03722
| | - Seongmin Im
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea 03722
| | - Changhun Lee
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea 03722
| | - Hyunwoong Lee
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea 03722
| | - Shi-Wei Chu
- Department of Physics National, Taiwan University, Taipei, Taiwan 10617
- Brain Research Center National, Tsing Hua University, Hsinchu, Taiwan 30013
| | - Aaron Ho-Pui Ho
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong 999077, China
| | - Donghyun Kim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea 03722
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Luo CH, Vyas S, Huang KY, Chu SW, Luo Y. Multiplane differential saturated excitation microscopy using varifocal lenses. Biomed Opt Express 2024; 15:953-964. [PMID: 38404334 PMCID: PMC10890851 DOI: 10.1364/boe.504807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/19/2023] [Accepted: 01/03/2024] [Indexed: 02/27/2024]
Abstract
Saturated excitation microscopy, which collects nonlinear fluorescence signals generated by saturation, has been proposed to improve three-dimensional spatial resolution. Differential saturated excitation (dSAX) microscopy can further improve the detection efficiency of a nonlinear fluorescence signal. By comparing signals obtained at different saturation levels, high spatial resolution can be achieved in a simple and efficient manner. High-resolution multiplane microscopy is perquisite for volumetric imaging of thick samples. To the best of our knowledge, no reports of multiplane dSAX have been made. Our aim is to obtain multiplane high-resolution optically sectioned images by adapting differential saturated excitation in confocal laser scanning fluorescence microscopy. To perform multiplane dSAX microscopy, a variable focus lens is employed in a telecentric design to achieve focus tunability with constant magnification and contrast throughout the axial scanning range. Multiplane fluorescence imaging of two different types of pollen grains shows improved resolution and contrast. Our system's imaging performance is evaluated using standard targets, and the results are compared with standard confocal microscopy. Using a simple and efficient method, we demonstrate multiplane high-resolution fluorescence imaging. We anticipate that high-spatial resolution combined with high-speed focus tunability with invariant contrast and magnification will be useful in performing 3D imaging of thick biological samples.
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Affiliation(s)
- Chi-Hao Luo
- Institute of Mechanical Engineering, National Taiwan University, Taipei, 10617, Taiwan
- Institute of Medical Device and Imaging, National Taiwan University, Taipei, 10617, Taiwan
| | - Sunil Vyas
- Institute of Medical Device and Imaging, National Taiwan University, Taipei, 10617, Taiwan
| | - Kuang-Yuh Huang
- Institute of Mechanical Engineering, National Taiwan University, Taipei, 10617, Taiwan
- Institute of Medical Device and Imaging, National Taiwan University, Taipei, 10617, Taiwan
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, 10051, Taiwan
| | - Yuan Luo
- Institute of Medical Device and Imaging, National Taiwan University, Taipei, 10617, Taiwan
- Department of Biomedical Engineering, National Taiwan University, 10051, Taiwan
- YongLin Institute of Health, National Taiwan University, Taipei, 10087, Taiwan
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Nishida K, Tseng PH, Chen YC, Wu PH, Yang CY, Yang JH, Chen WR, Pashina O, Petrov MI, Chen KP, Chu SW. Optical Bistability in Nanosilicon with Record Low Q-Factor. Nano Lett 2023; 23:11727-11733. [PMID: 38014963 DOI: 10.1021/acs.nanolett.3c03597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
We demonstrated optical bistability in an amorphous silicon Mie resonator with a size of ∼100 nm and Q-factor as low as ∼4 by utilizing photothermal and thermo-optical effects. We not only experimentally confirmed the steep intensity transition and the hysteresis in the scattering response from silicon nanocuboids but also established a physical model to numerically explain the underlying mechanism based on temperature-dependent competition between photothermal heating and heat dissipation. The transition between the bistable states offered particularly steep superlinearity of scattering intensity, reaching an effective nonlinearity order of ∼100th power over excitation intensity, leading to the potential of advanced optical switching devices and super-resolution microscopy.
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Affiliation(s)
- Kentaro Nishida
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Po-Hsueh Tseng
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Yu-Chieh Chen
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Pang-Han Wu
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Chi-Yin Yang
- Institute of Imaging and Biomedical Photonics, National Yang Ming Chiao Tung University, 301 Gaofa third Road, Tainan 711, Taiwan
| | - Jhen-Hong Yang
- Institute of Photonic System, National Yang Ming Chiao Tung University, 301 Gaofa third Road, Tainan 711, Taiwan
| | - Wei-Ruei Chen
- Institute of Photonic System, National Yang Ming Chiao Tung University, 301 Gaofa third Road, Tainan 711, Taiwan
| | - Olesiya Pashina
- Physics and Engineering Department, ITMO University, St. Petersburg 197101, Russia
| | - Mihail I Petrov
- Physics and Engineering Department, ITMO University, St. Petersburg 197101, Russia
| | - Kuo-Ping Chen
- Institute of Imaging and Biomedical Photonics, National Yang Ming Chiao Tung University, 301 Gaofa third Road, Tainan 711, Taiwan
- Institute of Photonics Technology, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu, Taiwan 30013, R.O.C
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei 10617, Taiwan
- Molecular Imaging Center, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei 10617, Taiwan
- Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
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Tang YL, Yen TH, Nishida K, Li CH, Chen YC, Zhang T, Pai CK, Chen KP, Li X, Takahara J, Chu SW. Multipole engineering by displacement resonance: a new degree of freedom of Mie resonance. Nat Commun 2023; 14:7213. [PMID: 37938215 PMCID: PMC10632421 DOI: 10.1038/s41467-023-43063-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 10/31/2023] [Indexed: 11/09/2023] Open
Abstract
The canonical studies on Mie scattering unravel strong electric/magnetic optical responses in nanostructures, laying foundation for emerging meta-photonic applications. Conventionally, the morphology-sensitive resonances hinge on the normalized frequency, i.e. particle size over wavelength, but non-paraxial incidence symmetry is overlooked. Here, through confocal reflection microscopy with a tight focus scanning over silicon nanostructures, the scattering point spread functions unveil distinctive spatial patterns featuring that linear scattering efficiency is maximal when the focus is misaligned. The underlying physical mechanism is the excitation of higher-order multipolar modes, not accessible by plane wave irradiation, via displacement resonance, which showcases a significant reduction of nonlinear response threshold, sign flip in all-optical switching, and spatial resolution enhancement. Our result fundamentally extends the century-old light scattering theory, and suggests new dimensions to tailor Mie resonances.
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Affiliation(s)
- Yu-Lung Tang
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Te-Hsin Yen
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Kentaro Nishida
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Chien-Hsuan Li
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Yu-Chieh Chen
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Tianyue Zhang
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China
| | - Chi-Kang Pai
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei, 10617, Taiwan
| | - Kuo-Ping Chen
- Institute of Imaging and Biomedical Photonics, National Yang Ming Chiao Tung University, 301 Gaofa 3rd Road, Tainan, 711, Taiwan
- Institute of Photonics Technologies, National Tsing Hua University, 301 Gaofa 3rd Road, Hsinchu, Taiwan
| | - Xiangping Li
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China.
| | - Junichi Takahara
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Photonics Center, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei, 10617, Taiwan.
- Molecular Imaging Center, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei, 10617, Taiwan.
- Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu, 30013, Taiwan.
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Huang GJ, Li CW, Lee PY, Su JX, Chao KC, Chu LA, Chiang AS, Cheng JX, Chen BH, Lu CH, Chu SW, Yang SD. Electronic Preresonance Stimulated Raman Scattering Spectromicroscopy Using Multiple-Plate Continuum. J Phys Chem B 2023; 127:6896-6902. [PMID: 37494414 DOI: 10.1021/acs.jpcb.3c02629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Stimulated Raman scattering (SRS) spectromicroscopy is a powerful technique that enables label-free detection of chemical bonds with high specificity. However, the low Raman cross section due to typical far-electronic resonance excitation seriously restricts the sensitivity and undermines its application to bio-imaging. To address this bottleneck, the electronic preresonance (EPR) SRS technique has been developed to enhance the Raman signals by shifting the excitation frequency toward the molecular absorption. A fundamental weakness of the previous demonstration is the lack of dual-wavelength tunability, making EPR-SRS only applicable to a limited number of species in the proof-of-concept experiment. Here, we demonstrate the EPR-SRS spectromicroscopy using a multiple-plate continuum (MPC) light source able to examine a single vibration mode with independently adjustable pump and Stokes wavelengths. In our experiments, the C═C vibration mode of Alexa 635 is interrogated by continuously scanning the pump-to-absorption frequency detuning throughout the entire EPR region enabled by MPC. The results exhibit 150-fold SRS signal enhancement and good agreement with the Albrecht A-term preresonance model. Signal enhancement is also observed in EPR-SRS images of the whole Drosophila brain stained with Alexa 635. With the improved sensitivity and potential to implement hyperspectral measurement, we envision that MPC-EPR-SRS spectromicroscopy can bring the Raman techniques closer to a routine in bio-imaging.
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Affiliation(s)
- Guan-Jie Huang
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Cheng-Wei Li
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Po-Yi Lee
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Jia-Xuan Su
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Kuo-Chuan Chao
- Brain Research Center, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Li-An Chu
- Brain Research Center, National Tsing Hua University, Hsinchu 300044, Taiwan
- Department of Biomedical Engineering & Environmental Sciences, National Tsing Hua University, Hsinchu 30044, Taiwan
| | - Ann-Shyn Chiang
- Brain Research Center, National Tsing Hua University, Hsinchu 300044, Taiwan
- Institute of Systems Neuroscience and Department of Life Science, National Tsing Hua University, Hsinchu 30044, Taiwan
| | - Ji-Xin Cheng
- Department of Electrical and Computer Engineering, Boston University, Boston, Massachusetts 02215, United States
| | - Bo-Han Chen
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Chih-Hsuan Lu
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 300044, Taiwan
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- Brain Research Center, National Tsing Hua University, Hsinchu 300044, Taiwan
- Molecular Imaging Center, National Taiwan University, Taipei 10617, Taiwan
| | - Shang-Da Yang
- Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 300044, Taiwan
- Brain Research Center, National Tsing Hua University, Hsinchu 300044, Taiwan
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Hsiao YT, Wu TY, Wu BK, Chu SW, Hsieh CL. Spinning disk interferometric scattering confocal microscopy captures millisecond timescale dynamics of living cells. Opt Express 2022; 30:45233-45245. [PMID: 36522930 DOI: 10.1364/oe.471935] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
Interferometric scattering (iSCAT) microscopy is a highly sensitive imaging technique that uses common-path interferometry to detect the linear scattering fields associated with samples. However, when measuring a complex sample, such as a biological cell, the superposition of the scattering signals from various sources, particularly those along the optical axis of the microscope objective, considerably complicates the data interpretation. Herein, we demonstrate high-speed, wide-field iSCAT microscopy in conjunction with confocal optical sectioning. Utilizing the multibeam scanning strategy of spinning disk confocal microscopy, our iSCAT confocal microscope acquires images at a rate of 1,000 frames per second (fps). The configurations of the spinning disk and the background correction procedures are described. The iSCAT confocal microscope is highly sensitive-individual 10 nm gold nanoparticles are successfully detected. Using high-speed iSCAT confocal imaging, we captured the rapid movements of single nanoparticles on the model membrane and single native vesicles in the living cells. Label-free iSCAT confocal imaging enables the detailed visualization of nanoscopic cell dynamics in their most native forms. This holds promise to unveil cell activities that are previously undescribed by fluorescence-based microscopy.
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Huang GJ, Lai PC, Shen MW, Su JX, Guo JY, Chao KC, Lin P, Cheng JX, Chu LA, Chiang AS, Chen BH, Lu CH, Chu SW, Yang SD. Towards stimulated Raman scattering spectro-microscopy across the entire Raman active region using a multiple-plate continuum. Opt Express 2022; 30:38975-38984. [PMID: 36258449 DOI: 10.1364/oe.469050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/17/2022] [Indexed: 06/16/2023]
Abstract
Stimulated Raman scattering (SRS) has attracted increasing attention in bio-imaging because of the ability toward background-free molecular-specific acquisitions without fluorescence labeling. Nevertheless, the corresponding sensitivity and specificity remain far behind those of fluorescence techniques. Here, we demonstrate SRS spectro-microscopy driven by a multiple-plate continuum (MPC), whose octave-spanning bandwidth (600-1300 nm) and high spectral energy density (∼1 nJ/cm-1) enable spectroscopic interrogation across the entire Raman active region (0-4000 cm-1), SRS imaging of a Drosophila brain, and electronic pre-resonance (EPR) detection of a fluorescent dye. We envision that utilizing MPC light source will substantially enhance the sensitivity and specificity of SRS by implementing EPR mode and spectral multiplexing via accessing three or more coherent wavelengths.
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Abstract
Silicon nanophotonics has attracted significant attention because of its unique optical properties such as efficient light confinement and low non-radiative loss. For practical applications such as all-optical switch, optical nonlinearity is a prerequisite, but the nonlinearity of silicon is intrinsically weak. Recently, we discovered a giant nonlinearity of scattering from a single silicon nanostructure by combining Mie resonance enhanced photo-thermal and thermo-optic effects. Since scattering and absorption are closely linked in Mie theory, we expect that absorption, as well as heating, of the silicon nanostructure shall exhibit similar nonlinear behaviors. In this work, we experimentally measure the temperature rise of a silicon nanoblock by in situ Raman spectroscopy, explicitly demonstrating the connection between nonlinear scattering and nonlinear heating. The results agree well with finite-element simulation based on the photo-thermo-optic effect, manifesting that the nonlinear effect is the coupled consequence of the red shift between scattering and absorption spectra. Our work not only unravels the nonlinear absorption in a silicon Mie-resonator but also offers a quantitative analytic model to better understand the complete photo-thermo-optic properties of silicon nanostructures, providing a new perspective toward practical silicon photonics applications.
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Affiliation(s)
- Chien-Hsuan Li
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Yu-Lung Tang
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Junichi Takahara
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., Taipei 10617, Taiwan
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Chien YF, Lin JY, Yeh PT, Hsu KJ, Tsai YH, Chen SK, Chu SW. Dual GRIN lens two-photon endoscopy for high-speed volumetric and deep brain imaging. Biomed Opt Express 2021; 12:162-172. [PMID: 33659072 PMCID: PMC7899523 DOI: 10.1364/boe.405738] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/22/2020] [Accepted: 11/18/2020] [Indexed: 05/30/2023]
Abstract
Studying neural connections and activities in vivo is fundamental to understanding brain functions. Given the cm-size brain and three-dimensional neural circuit dynamics, deep-tissue, high-speed volumetric imaging is highly desirable for brain study. With sub-micrometer spatial resolution, intrinsic optical sectioning, and deep-tissue penetration capability, two-photon microscopy (2PM) has found a niche in neuroscience. However, the current 2PM typically relies on a slow axial scan for volumetric imaging, and the maximal penetration depth is only about 1 mm. Here, we demonstrate that by integrating a gradient-index (GRIN) lens and a tunable acoustic GRIN (TAG) lens into 2PM, both penetration depth and volume-imaging rate can be significantly improved. Specifically, an ∼ 1-cm long GRIN lens allows imaging relay from any target region of a mouse brain, while a TAG lens provides a sub-second volume rate via a 100 kHz ∼ 1 MHz axial scan. This technique enables the study of calcium dynamics in cm-deep brain regions with sub-cellular and sub-second spatiotemporal resolution, paving the way for interrogating deep-brain functional connectome.
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Affiliation(s)
- Yu-Feng Chien
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Jyun-Yi Lin
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Po-Ting Yeh
- Department of Life Science, National Taiwan University, Taipei 10617, Taiwan
- Taiwan International Graduate Program in Interdisciplinary Neuroscience, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan
| | - Kuo-Jen Hsu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yu-Hsuan Tsai
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Shih-Kuo Chen
- Department of Life Science, National Taiwan University, Taipei 10617, Taiwan
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
- Molecular Imaging Center, National Taiwan University, Taipei 10617, Taiwan
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Duh YS, Nagasaki Y, Tang YL, Wu PH, Cheng HY, Yen TH, Ding HX, Nishida K, Hotta I, Yang JH, Lo YP, Chen KP, Fujita K, Chang CW, Lin KH, Takahara J, Chu SW. Giant photothermal nonlinearity in a single silicon nanostructure. Nat Commun 2020; 11:4101. [PMID: 32796839 PMCID: PMC7427991 DOI: 10.1038/s41467-020-17846-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 07/21/2020] [Indexed: 11/08/2022] Open
Abstract
Silicon photonics have attracted significant interest because of their potential in integrated photonics components and all-dielectric meta-optics elements. One major challenge is to achieve active control via strong photon-photon interactions, i.e. optical nonlinearity, which is intrinsically weak in silicon. To boost the nonlinear response, practical applications rely on resonant structures such as microring resonators or photonic crystals. Nevertheless, their typical footprints are larger than 10 μm. Here, we show that 100 nm silicon nano-resonators exhibit a giant photothermal nonlinearity, yielding 90% reversible and repeatable modulation from linear scattering response at low excitation intensities. The equivalent nonlinear index is five-orders larger compared with bulk, based on Mie resonance enhanced absorption and high-efficiency heating in thermally isolated nanostructures. Furthermore, the nanoscale thermal relaxation time reaches nanosecond. This large and fast nonlinearity leads to potential applications for GHz all-optical control at the nanoscale and super-resolution imaging of silicon.
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Grants
- MOST-105-2628-M-002-010-MY4 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- MOST-108-2321-B-002-058-MY2 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- MOST-108-2112-M-001-027 Ministry of Science and Technology, Taiwan (Ministry of Science and Technology of Taiwan)
- Core-to-Core Program, A. Advanced Research Networks MEXT | Japan Society for the Promotion of Science (JSPS)
- F-17-OS-0011 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- S-17-OS-0011 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
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Affiliation(s)
- Yi-Shiou Duh
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., 10617, Taipei, Taiwan
| | - Yusuke Nagasaki
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yu-Lung Tang
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., 10617, Taipei, Taiwan
| | - Pang-Han Wu
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., 10617, Taipei, Taiwan
| | - Hao-Yu Cheng
- Institute of Physics, Academia Sinica, 128, Sec. 2, Academia Rd., 11529, Taipei, Taiwan
| | - Te-Hsin Yen
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., 10617, Taipei, Taiwan
| | - Hou-Xian Ding
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., 10617, Taipei, Taiwan
| | - Kentaro Nishida
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- AIST-Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, AIST, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Ikuto Hotta
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Jhen-Hong Yang
- Institute of Photonic System, National Chiao Tung University, 301 Gaofa 3rd Road, 711, Tainan, Taiwan
| | - Yu-Ping Lo
- Institute of Imaging and Biomedical Photonics, National Chiao Tung University, 301 Gaofa 3rd Road, Tainan, 711, Taiwan
| | - Kuo-Ping Chen
- Institute of Imaging and Biomedical Photonics, National Chiao Tung University, 301 Gaofa 3rd Road, Tainan, 711, Taiwan
| | - Katsumasa Fujita
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- AIST-Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, AIST, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Chih-Wei Chang
- Center for Condensed Matter Sciences, National Taiwan University, 1, Sec 4, Roosevelt Rd., 10617, Taipei, Taiwan
| | - Kung-Hsuan Lin
- Institute of Physics, Academia Sinica, 128, Sec. 2, Academia Rd., 11529, Taipei, Taiwan.
| | - Junichi Takahara
- Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Photonics Center, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Rd., 10617, Taipei, Taiwan.
- Molecular Imaging Center, National Taiwan University, 1, Sec 4, Roosevelt Rd., 10617, Taipei, Taiwan.
- Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, 30013, Hsinchu, Taiwan.
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Chang W, Hsiao CC, Lin YY, Chu LA, Swindlehurst AL, Chu SW, Chiang AS, Wu SC. Drosophila Brain Functional Data Analysis: A Unified Framework. Annu Int Conf IEEE Eng Med Biol Soc 2020; 2020:1088-1091. [PMID: 33018175 DOI: 10.1109/embc44109.2020.9175269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A unified framework for the analysis of fluorescence data taken by a two-photon imaging system is presented. As in the processing of blood-oxygen-level-dependent signals of functional magnetic resonance imaging, the acquired functional images have to be co-registered with a structural brain atlas before delineating the regions activated by a given stimulus. The voxels whose calcium traces are highly correlated with the predicted responses are demarcated without the need for subjective reasoning. Experimental data acquired while presenting olfactory stimuli are used to demonstrate the efficacy of the proposed schemes. The results indicate that the functional images of a Drosophila individual can be normalized into a standard stereotactic space, and the expected brain regions can be delineated adequately. This framework provides an opportunity to enable the development of a Drosophila functional connectome database.
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Huang C, Tai CY, Yang KP, Chang WK, Hsu KJ, Hsiao CC, Wu SC, Lin YY, Chiang AS, Chu SW. All-Optical Volumetric Physiology for Connectomics in Dense Neuronal Structures. iScience 2019; 22:133-146. [PMID: 31765994 PMCID: PMC6883334 DOI: 10.1016/j.isci.2019.11.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 09/19/2019] [Accepted: 11/04/2019] [Indexed: 01/04/2023] Open
Abstract
All-optical physiology (AOP) manipulates and reports neuronal activities with light, allowing for interrogation of neuronal functional connections with high spatiotemporal resolution. However, contemporary high-speed AOP platforms are limited to single-depth or discrete multi-plane recordings that are not suitable for studying functional connections among densely packed small neurons, such as neurons in Drosophila brains. Here, we constructed a 3D AOP platform by incorporating single-photon point stimulation and two-photon high-speed volumetric recordings with a tunable acoustic gradient-index (TAG) lens. We demonstrated the platform effectiveness by studying the anterior visual pathway (AVP) of Drosophila. We achieved functional observation of spatiotemporal coding and the strengths of calcium-sensitive connections between anterior optic tubercle (AOTU) sub-compartments and >70 tightly assembled 2-μm bulb (BU) microglomeruli in 3D coordinates with a single trial. Our work aids the establishment of in vivo 3D functional connectomes in neuron-dense brain areas. All-optical volumetric physiology = precise stimulation + fast volumetric recording Precise single-photon point stimulation among genetically defined neurons 3D two-photon imaging by an acoustic gradient-index lens for dense neural structures Observation of 3D functional connectivity in Drosophila anterior visual pathway
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Affiliation(s)
- Chiao Huang
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Chu-Yi Tai
- Institute of Biotechnology, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
| | - Kai-Ping Yang
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Wei-Kun Chang
- Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
| | - Kuo-Jen Hsu
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Road, Taipei 10617, Taiwan; Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
| | - Ching-Chun Hsiao
- Department of Engineering and System Science, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
| | - Shun-Chi Wu
- Department of Engineering and System Science, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan
| | - Yen-Yin Lin
- Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan.
| | - Ann-Shyn Chiang
- Institute of Biotechnology, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan; Brain Research Center, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan; Institute of Systems Neuroscience, National Tsing Hua University, 101, Sec 2, Guangfu Road, Hsinchu 30013, Taiwan; Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80780, Taiwan; Graduate Institute of Clinical Medical Science, China Medical University, Taichung 40402, Taiwan; Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli 35053, Taiwan; Kavli Institute for Brain and Mind, University of California, San Diego, CA 92161, USA.
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, 1, Sec 4, Roosevelt Road, Taipei 10617, Taiwan; Molecular Imaging Center, National Taiwan University, 1, Sec 4, Roosevelt Road, Taipei 10617, Taiwan.
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Jagadale TC, Murali DS, Chu SW. Nonlinear absorption and scattering of a single plasmonic nanostructure characterized by x-scan technique. Beilstein J Nanotechnol 2019; 10:2182-2191. [PMID: 31807404 PMCID: PMC6880810 DOI: 10.3762/bjnano.10.211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/16/2019] [Indexed: 05/26/2023]
Abstract
Nonlinear nanoplasmonics is a largely unexplored research area that paves the way for many exciting applications, such as nanolasers, nanoantennas, and nanomodulators. In the field of nonlinear nanoplasmonics, it is highly desirable to characterize the nonlinearity of the optical absorption and scattering of single nanostructures. Currently, the common method to quantify optical nonlinearity is the z-scan technique, which yields real and imaginary parts of the permittivity by moving a thin sample with a laser beam. However, z-scan typically works with thin films, and thus acquires nonlinear responses from ensembles of nanostructures, not from single ones. In this work, we present an x-scan technique that is based on a confocal laser scanning microscope equipped with forward and backward detectors. The two-channel detection offers the simultaneous quantification for the nonlinear behavior of scattering, absorption and total attenuation by a single nanostructure. At low excitation intensities, both scattering and absorption responses are linear, thus confirming the linearity of the detection system. At high excitation intensities, we found that the nonlinear response can be derived directly from the point spread function of the x-scan images. Exceptionally large nonlinearities of both scattering and absorption are unraveled simultaneously for the first time. The present study not only provides a novel method for characterizing nonlinearity of a single nanostructure, but also reports surprisingly large plasmonic nonlinearities.
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Affiliation(s)
- Tushar C Jagadale
- Department of Physics, National Taiwan University, No.1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
- Technical Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Dhanya S Murali
- Department of Physics, National Taiwan University, No.1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, No.1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
- Molecular Imaging Centre, National Taiwan University, No.1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
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14
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Hsu KJ, Lin YY, Lin YY, Su K, Feng KL, Wu SC, Lin YC, Chiang AS, Chu SW. Millisecond two-photon optical ribbon imaging for small-animal functional connectome study. Opt Lett 2019; 44:3190-3193. [PMID: 31259918 DOI: 10.1364/ol.44.003190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 05/22/2019] [Indexed: 06/09/2023]
Abstract
We developed a high-speed two-photon optical ribbon imaging system, which combines galvo-mirrors for an arbitrary curve scan on a lateral plane and a tunable acoustic gradient-index lens for a 100 kHz-1 MHz axial scan. The system provides micrometer/millisecond spatiotemporal resolutions, which enable continuous readout of functional dynamics from small and densely packed neurons in a living adult Drosophila brain. Compared to sparse sampling techniques, the ribbon imaging modality avoids motion artifacts. Combined with a Drosophila anatomical connectome database, which is the most complete among all model animals, this technique paves the way toward establishing whole-brain functional connectome.
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Hsu KJ, Lin YY, Chiang AS, Chu SW. Optical properties of adult Drosophila brains in one-, two-, and three-photon microscopy. Biomed Opt Express 2019; 10:1627-1637. [PMID: 31086697 PMCID: PMC6484994 DOI: 10.1364/boe.10.001627] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 01/23/2019] [Accepted: 02/17/2019] [Indexed: 06/09/2023]
Abstract
Drosophila is widely used in connectome studies due to its small brain size, sophisticated genetic tools, and the most complete single-neuron-based anatomical brain map. Surprisingly, even the brain thickness is only 200-μm, common Ti:sapphire-based two-photon excitation cannot penetrate, possibly due to light aberration/scattering of trachea. Here we quantitatively characterized scattering and light distortion of trachea-filled tissues, and found that trachea-induced light distortion dominates at long wavelength by comparing one-photon (488-nm), two-photon (920-nm), and three-photon (1300-nm) excitations. Whole-Drosophila-brain imaging is achieved by reducing tracheal light aberration/scattering via brain-degassing or long-wavelength excitation at 1300-nm. Our work paves the way toward constructing whole-brain connectome in a living Drosophila.
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Affiliation(s)
- Kuo-Jen Hsu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yen-Yin Lin
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ann-Shyn Chiang
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
- Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu 30013, Taiwan
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 80780, Taiwan
- Kavli Institute for Brain and Mind, University of California at San Diego, La Jolla, CA 92093-0526, USA
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- Molecular Imaging Center, National Taiwan University, Taipei 10617, Taiwan
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Lin HY, Chu LA, Yang H, Hsu KJ, Lin YY, Lin KH, Chu SW, Chiang AS. Imaging through the Whole Brain of Drosophila at λ/20 Super-resolution. iScience 2019; 14:164-170. [PMID: 30978667 PMCID: PMC6460254 DOI: 10.1016/j.isci.2019.03.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/27/2019] [Accepted: 03/19/2019] [Indexed: 11/26/2022] Open
Abstract
Recently, many super-resolution technologies have been demonstrated, significantly affecting biological studies by observation of cellular structures down to nanometer precision. However, current super-resolution techniques mostly rely on wavefront engineering or wide-field imaging of signal blinking or fluctuation, and thus imaging depths are limited due to tissue scattering or aberration. Here we present a technique that is capable of imaging through an intact Drosophila brain with 20-nm lateral resolution at ∼200 μm depth. The spatial resolution is provided by molecular localization of a photoconvertible fluorescent protein Kaede, whose red form is found to exhibit blinking state. The deep-tissue observation is enabled by optical sectioning of spinning disk microscopy, as well as reduced scattering from optical clearing. Together these techniques are readily available for many biologists, providing three-dimensional resolution of densely entangled dendritic fibers in a complete Drosophila brain. The method paves the way toward whole-brain neural network studies and is applicable to other high-resolution bioimaging.
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Affiliation(s)
- Han-Yuan Lin
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Li-An Chu
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan; Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Hsuan Yang
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
| | - Kuo-Jen Hsu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan; Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yen-Yin Lin
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Keng-Hui Lin
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan.
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan; Molecular Imaging Center, National Taiwan University, Taipei 10617, Taiwan.
| | - Ann-Shyn Chiang
- Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan; Institute of Physics, Academia Sinica, Taipei 11529, Taiwan; Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu 30013, Taiwan; Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli 35053, Taiwan; Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA 92093-0526, USA.
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Chu SW. Optical microscopy approaches angstrom precision, in 3D! Light Sci Appl 2019; 8:117. [PMID: 31839937 PMCID: PMC6904455 DOI: 10.1038/s41377-019-0226-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
By coupling dye molecules with a graphene layer and localizing the molecules through quantification of fluorescence lifetime quenching, a novel imaging system offers unprecedented 1-nm resolution with angstrom precision in the axial dimension.
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Affiliation(s)
- Shi-Wei Chu
- Department of Physics and Molecular Imaging Center, Taiwan University, https://www.ntu.edu.tw
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18
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Hsu KJ, Li KY, Lin YY, Chiang AS, Chu SW. Optimizing depth-of-field extension in optical sectioning microscopy techniques using a fast focus-tunable lens. Opt Express 2017; 25:16783-16794. [PMID: 28789179 DOI: 10.1364/oe.25.016783] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/05/2017] [Indexed: 05/18/2023]
Abstract
Volume imaging based on a fast focus-tunable lens (FTL) allows three-dimensional (3D) observation within milliseconds by extending the depth-of-field (DOF) with sub-micrometer transverse resolution on optical sectioning microscopes. However, the previously published DOF extensions were neither axially uniform nor fit with theoretical prediction. In this work, complete theoretical treatments of focus extension with confocal and various multiphoton microscopes are established to correctly explain the previous results. Moreover, by correctly placing the FTL and properly adjusting incident beam diameter, a uniform DOF is achieved in which the actual extension nicely agrees with the theory. Our work not only provides a theoretical platform for volumetric imaging with FTL but also demonstrates the optimized imaging condition.
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Tseng YC, Chu SW. High spatio-temporal-resolution detection of chlorophyll fluorescence dynamics from a single chloroplast with confocal imaging fluorometer. Plant Methods 2017; 13:43. [PMID: 28546824 PMCID: PMC5442853 DOI: 10.1186/s13007-017-0194-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Accepted: 05/18/2017] [Indexed: 05/26/2023]
Abstract
BACKGROUND Chlorophyll fluorescence (CF) is a key indicator to study plant physiology or photosynthesis efficiency. Conventionally, CF is characterized by fluorometers, which only allows ensemble measurement through wide-field detection. For imaging fluorometers, the typical spatial and temporal resolutions are on the order of millimeter and second, far from enough to study cellular/sub-cellular CF dynamics. In addition, due to the lack of optical sectioning capability, conventional imaging fluorometers cannot identify CF from a single cell or even a single chloroplast. RESULTS AND DISCUSSION Here we demonstrated a fluorometer based on confocal imaging, that not only provides high contrast images, but also allows CF measurement with spatiotemporal resolution as high as micrometer and millisecond. CF transient (the Kautsky curve) from a single chloroplast is successfully obtained, with both the temporal dynamics and the intensity dependences corresponding well to the ensemble measurement from conventional studies. The significance of confocal imaging fluorometer is to identify the variation among individual chloroplasts, e.g. the temporal position of the P-S-M phases, and the half-life period of P-T decay in the Kautsky curve, that are not possible to analyze with wide-field techniques. A linear relationship is found between excitation intensity and the temporal positions of P-S-M peaks/valleys in the Kautsky curve. Based on the CF transients, the photosynthetic quantum efficiency is derived with spatial resolution down to a single chloroplast. In addition, an interesting 6-order increase in excitation intensity is found between wide-field and confocal fluorometers, whose pixel integration time and optical sectioning may account for this substantial difference. CONCLUSION Confocal imaging fluorometers provide micrometer and millisecond CF characterization, opening up unprecedented possibilities toward detailed spatiotemporal analysis of CF transients and its propagation dynamics, as well as photosynthesis efficiency analysis, on the scale of organelles, in a living plant.
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Affiliation(s)
- Yi-Chin Tseng
- Department of Physics, National Taiwan University, No. 1, Section 4, Roosevelt Rd, Da’an District, Taipei City, 10617 Taiwan
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, No. 1, Section 4, Roosevelt Rd, Da’an District, Taipei City, 10617 Taiwan
- Molecular Imaging Center, National Taiwan University, No. 81, Changxing Street, Da’an District, Taipei, 10672 Taiwan
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20
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Shen PT, Sivan Y, Lin CW, Liu HL, Chang CW, Chu SW. Temperature- and roughness- dependent permittivity of annealed/unannealed gold films. Opt Express 2016; 24:19254-19263. [PMID: 27557205 DOI: 10.1364/oe.24.019254] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/02/2016] [Indexed: 06/06/2023]
Abstract
Intrinsic absorption and subsequent heat generation have long been issues for metal-based plasmonics. Recently, thermo-plasmonics, which takes the advantage of such a thermal effect, is emerging as an important branch of plasmonics. However, although significant temperature increase is involved, characterization of metal permittivity at different temperatures and corresponding thermo-derivative are lacking. Here we measure gold permittivity from 300K to 570K, which the latter is enough for gold annealing. More than one order difference in thermo-derivative is revealed between annealed and unannealed films, resulting in a large variation of plasmonic properties. In addition, an unusual increase of imaginary permittivity after annealing is found. Both these effects can be attributed to the increased surface roughness incurred by annealing. Our results are valuable for characterizing extensively used unannealed nanoparticles, or annealed nanostructures, as building blocks in future thermo-nano-plasmonic systems.
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Su IC, Hsu KJ, Shen PT, Lin YY, Chu SW. 3D resolution enhancement of deep-tissue imaging based on virtual spatial overlap modulation microscopy. Opt Express 2016; 24:16238-46. [PMID: 27464077 DOI: 10.1364/oe.24.016238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
During the last decades, several resolution enhancement methods for optical microscopy beyond diffraction limit have been developed. Nevertheless, those hardware-based techniques typically require strong illumination, and fail to improve resolution in deep tissue. Here we develop a high-speed computational approach, three-dimensional virtual spatial overlap modulation microscopy (3D-vSPOM), which immediately solves the strong-illumination issue. By amplifying only the spatial frequency component corresponding to the un-scattered point-spread-function at focus, plus 3D nonlinear value selection, 3D-vSPOM shows significant resolution enhancement in deep tissue. Since no iteration is required, 3D-vSPOM is much faster than iterative deconvolution. Compared to non-iterative deconvolution, 3D-vSPOM does not need a priori information of point-spread-function at deep tissue, and provides much better resolution enhancement plus greatly improved noise-immune response. This method is ready to be amalgamated with two-photon microscopy or other laser scanning microscopy to enhance deep-tissue resolution.
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Li PY, Tsao Y, Liu YJ, Lou ZX, Lee WL, Chu SW, Chang CW. Unusual imaging properties of superresolution microspheres. Opt Express 2016; 24:16479-86. [PMID: 27464101 DOI: 10.1364/oe.24.016479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We employ a self-assembly method to fabricate dielectric microsphere arrays that can be transferred to any desired positions. The arrays not only enable far-field, broad-band, high-speed, large-area, and wide-angle field of views but also achieve superresolution reaching λ/6.4. We also find that many proposed theories are insufficient to explain the imaging properties; including the achieved superresolution, effects of immersion, and unusual size-dependent magnification. The half-immersed microspheres certainly do not behave like any ordinary solid immersion lenses and new mechanisms must be incorporated to explain their unusual imaging properties.
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Wu HY, Huang YT, Shen PT, Lee H, Oketani R, Yonemaru Y, Yamanaka M, Shoji S, Lin KH, Chang CW, Kawata S, Fujita K, Chu SW. Ultrasmall all-optical plasmonic switch and its application to superresolution imaging. Sci Rep 2016; 6:24293. [PMID: 27063920 PMCID: PMC4827031 DOI: 10.1038/srep24293] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/21/2016] [Indexed: 12/03/2022] Open
Abstract
Because of their exceptional local-field enhancement and ultrasmall mode volume, plasmonic components can integrate photonics and electronics at nanoscale, and active control of plasmons is the key. However, all-optical modulation of plasmonic response with nanometer mode volume and unity modulation depth is still lacking. Here we show that scattering from a plasmonic nanoparticle, whose volume is smaller than 0.001 μm3, can be optically switched off with less than 100 μW power. Over 80% modulation depth is observed, and shows no degradation after repetitive switching. The spectral bandwidth approaches 100 nm. The underlying mechanism is suggested to be photothermal effects, and the effective single-particle nonlinearity reaches nearly 10−9 m2/W, which is to our knowledge the largest record of metallic materials to date. As a novel application, the non-bleaching and unlimitedly switchable scattering is used to enhance optical resolution to λ/5 (λ/9 after deconvolution), with 100-fold less intensity requirement compared to similar superresolution techniques. Our work not only opens up a new field of ultrasmall all-optical control based on scattering from a single nanoparticle, but also facilitates superresolution imaging for long-term observation.
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Affiliation(s)
- Hsueh-Yu Wu
- Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Yen-Ta Huang
- Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Po-Ting Shen
- Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Hsuan Lee
- Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Ryosuke Oketani
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0851, Japan
| | - Yasuo Yonemaru
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0851, Japan
| | - Masahito Yamanaka
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0851, Japan
| | - Satoru Shoji
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0851, Japan
| | - Kung-Hsuan Lin
- Institute of Physics, Academia Sinica, 128 Sec. 2, Academia Rd., Nankang, Taipei 11529, Taiwan
| | - Chih-Wei Chang
- Center for Condensed Matter Sciences, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
| | - Satoshi Kawata
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0851, Japan
| | - Katsumasa Fujita
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0851, Japan
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan.,Molecular Imaging Center, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
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Lee H, Li KY, Huang YT, Shen PT, Deka G, Oketani R, Yonemaru Y, Yamanaka M, Fujita K, Chu SW. Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle. J Vis Exp 2016. [PMID: 26780248 DOI: 10.3791/53338] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus have potential applications in nonlinear optics, which requires extraordinary optical intensity. One of the most studied nonlinearities in plasmonics is nonlinear absorption, including saturation and reverse saturation behaviors. Although scattering and absorption in nanoparticles are closely correlated by the Mie theory, there has been no report of nonlinearities in plasmonic scattering until very recently. Last year, not only saturation, but also reverse saturation of scattering in an isolated plasmonic particle was demonstrated for the first time. The results showed that saturable scattering exhibits clear wavelength dependence, which seems to be directly linked to the localized surface plasmon resonance (LSPR). Combined with the intensity-dependent measurements, the results suggest the possibility of a common mechanism underlying the nonlinear behaviors of scattering and absorption. These nonlinearities of scattering from a single gold nanosphere (GNS) are widely applicable, including in super-resolution microscopy and optical switches. In this paper, it is described in detail how to measure nonlinearity of scattering in a single GNP and how to employ the super-resolution technique to enhance the optical imaging resolution based on saturable scattering. This discovery features the first super-resolution microscopy based on nonlinear scattering, which is a novel non-bleaching contrast method that can achieve a resolution as low as l/8 and will potentially be useful in biomedicine and material studies.
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Affiliation(s)
- Hsuan Lee
- Department of Physics, National Taiwan University
| | - Kuan-Yu Li
- Department of Physics, National Taiwan University
| | - Yen-Ta Huang
- Department of Physics, National Taiwan University
| | - Po-Ting Shen
- Department of Physics, National Taiwan University
| | | | | | | | | | | | - Shi-Wei Chu
- Department of Physics, National Taiwan University; Molecular Imaging Center, National Taiwan University;
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Chu SW, Kawata S, Fujita K. C4-O-01Super-resolution imaging based on nonlinearities of plasmonic scattering. Microscopy (Oxf) 2015. [DOI: 10.1093/jmicro/dfv193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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26
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Chen PF, Liu CL, Lin WK, Chen KC, Chou PT, Chu SW. Fluorescence depletion properties of insulin-gold nanoclusters. Biomed Opt Express 2015; 6:3066-73. [PMID: 26309767 PMCID: PMC4541531 DOI: 10.1364/boe.6.003066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 07/23/2015] [Accepted: 07/23/2015] [Indexed: 05/12/2023]
Abstract
Insulin-gold nanoclusters exhibit outstanding biocompatibility, photostability, and fluorescence quantum efficiency. However, they have never been used in superresolution microscopy, which requires nonlinear switching or saturation of fluorescence. Here we examine the fluorescence and stimulated emission depletion properties of gold nanoclusters. Their bleaching rate is very slow, demonstrating superior photostability. Surprisingly, however, the best depletion efficiency is less than 70%, whereas the depletion intensity requirement is much higher than the expectation from a simple two-level model. Fluorescence lifetime measurement revealed two distinct lifetime components, which indicate intersystem and reverse intersystem crossing during excitation. Based on population dynamic calculation, excellent agreement of the maximal depletion efficiency is found. Our work not only features the first examination of STED with metallic clusters, but also reveals the significance of molecular transition dynamics when considering a STED labeling.
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Affiliation(s)
- Po-Fu Chen
- Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Chien-Liang Liu
- Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Wei-Kuan Lin
- Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Kuan-Chieh Chen
- Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Pi-Tai Chou
- Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Shi-Wei Chu
- Department of Physics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
- NTU Molecular Imaging Center, No. 81, Changxing St., Taipei 10672, Taiwan
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Lee H, Oketani R, Huang YT, Li KY, Yonemaru Y, Yamanaka M, Kawata S, Fujita K, Chu SW. Point spread function analysis with saturable and reverse saturable scattering. Opt Express 2014; 22:26016-26022. [PMID: 25401635 DOI: 10.1364/oe.22.026016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nonlinear plasmonics has attracted a lot of interests due to its wide applications. Recently, we demonstrated saturation and reverse saturation of scattering from a single plasmonic nanoparticle, which exhibits extremely narrow side lobes and central peaks in scattering images [ACS Photonics 1(1), 32 (2014)]. It is desirable to extract the reversed saturated part to further enhance optical resolution. However, such separation is not possible with conventional confocal microscope. Here we combine reverse saturable scattering and saturated excitation (SAX) microscopy. With quantitative analyses of amplitude and phase of SAX signals, unexpectedly high-order nonlinearities are revealed. Our result provides greatly reduced width in point spread function of scattering-based optical microscopy. It will find applications in not only nonlinear material analysis, but also high-resolution biomedical microscopy.
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Chen MY, Zhuo GY, Chen KC, Wu PC, Hsieh TY, Liu TM, Chu SW. Multiphoton imaging to identify grana, stroma thylakoid, and starch inside an intact leaf. BMC Plant Biol 2014; 14:175. [PMID: 24969621 PMCID: PMC4104400 DOI: 10.1186/1471-2229-14-175] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 06/18/2014] [Indexed: 05/24/2023]
Abstract
BACKGROUND Grana and starch are major functional structures for photosynthesis and energy storage of plant, respectively. Both exhibit highly ordered molecular structures and appear as micrometer-sized granules inside chloroplasts. In order to distinguish grana and starch, we used multiphoton microscopy, with simultaneous acquisition of two-photon fluorescence (2PF) and second harmonic generation (SHG) signals. SHG is sensitive to crystallized structures while 2PF selectively reveals the distribution of chlorophyll. RESULT Three distinct microstructures with different contrasts were observed, i.e. "SHG dominates", "2PF dominates", and "SHG collocated with 2PF". It is known that starch and grana both emit SHG due to their highly crystallized structures, and no autofluorescence is emitted from starch, so the "SHG dominates" contrast should correspond to starch. The contrast of "SHG collocated with 2PF" is assigned to be grana, which exhibit crystallized structure with autofluorescent chlorophyll. The "2PF dominates" contrast should correspond to stroma thylakoid, which is a non-packed membrane structure with chrolophyll. The contrast assignment is further supported by fluorescence lifetime measurement. CONCLUSION We have demonstrated a straightforward and noninvasive method to identify the distribution of grana and starch within an intact leaf. By merging the 2PF and SHG images, grana, starch and stroma thylakoid can be visually distinguished. This approach can be extended to the observation of 3D grana distribution and their dynamics in living plants.
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Affiliation(s)
| | | | | | | | | | | | - Shi-Wei Chu
- Department of Physics, National Taiwan University, Taipei, Taiwan.
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Chen JY, Ho CY, Lu ML, Chu LJ, Chen KC, Chu SW, Chen W, Mou CY, Chen YF. Efficient spin-light emitting diodes based on InGaN/GaN quantum disks at room temperature: a new self-polarized paradigm. Nano Lett 2014; 14:3130-3137. [PMID: 24807793 DOI: 10.1021/nl5003312] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A well-behaved spin-light emitting diode (LED) composed of InGaN/GaN multiple quantum disks (MQDs), ferromagnetic contact, and Fe3O4 nanoparticles has been designed, fabricated, and characterized. The degree of circular polarization of electroluminescence (EL) can reach up to a high value of 10.9% at room temperature in a low magnetic field of 0.35 T, which overcomes a very low degree of spin polarization in nitride semiconductors due to the weak spin-orbit interaction. Several underlying mechanisms play significant roles simultaneously in this newly designed device for the achievement of such a high performance. Most of all, the vacancy between nanodisks can be filled by half-metal nanoparticles with suitable energy band alignment, which enables selective transfer of spin polarized electrons and holes and leads to the enhanced output spin polarization of LED. Unlike previously reported mechanisms, this new process leads to a weak dependence of spin relaxation on temperature. Additionally, the internal strain in planar InGaN/GaN multiple quantum wells can be relaxed in the nanodisk formation process, which leads to the disappearance of Rashba Hamiltonian and enhances the spin relaxation time. Our approach therefore opens up a new route for the further research and development of semiconductor spintronics.
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Affiliation(s)
- J Y Chen
- Department of Physics, National Taiwan University , Taipei 106, Taiwan
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30
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Chu SW, Su TY, Oketani R, Huang YT, Wu HY, Yonemaru Y, Yamanaka M, Lee H, Zhuo GY, Lee MY, Kawata S, Fujita K. Measurement of a saturated emission of optical radiation from gold nanoparticles: application to an ultrahigh resolution microscope. Phys Rev Lett 2014; 112:017402. [PMID: 24483931 DOI: 10.1103/physrevlett.112.017402] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Indexed: 05/26/2023]
Abstract
We show that scattering from a single gold nanoparticle is saturable for the first time. Wavelength-dependent study reveals that the saturation behavior is governed by depletion of surface plasmon resonance, not the thermal effect. We observed interesting flattening of the point spread function of scattering from a single nanoparticle due to saturation. By extracting the saturated part of scattering via temporal modulation, we achieve λ/8 point spread function in far-field imaging with unambiguous separation of adjacent particles.
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Affiliation(s)
- Shi-Wei Chu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan, Republic of China and Molecular Imaging Center, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Tung-Yu Su
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Ryosuke Oketani
- Department of Applied Physics, Osaka University, 565-0871 Osaka, Japan
| | - Yen-Ta Huang
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Hsueh-Yu Wu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Yasuo Yonemaru
- Department of Applied Physics, Osaka University, 565-0871 Osaka, Japan
| | - Masahito Yamanaka
- Department of Applied Physics, Osaka University, 565-0871 Osaka, Japan
| | - Hsuan Lee
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Guan-Yu Zhuo
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Ming-Ying Lee
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Satoshi Kawata
- Department of Applied Physics, Osaka University, 565-0871 Osaka, Japan
| | - Katsumasa Fujita
- Department of Applied Physics, Osaka University, 565-0871 Osaka, Japan
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Wahab MA, Chu SW, Anand C, Ha CS. Synthesis and characterization of multifunctional periodic mesoporous organosilica from diureidophenylene bridged organosilica precursor. J Nanosci Nanotechnol 2012; 12:4531-4539. [PMID: 22905496 DOI: 10.1166/jnn.2012.6215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This paper reports the periodic mesoporous organosilicas (PMOs) functionalised with newly synthesized bis-silylated (1,1(1,4-phenylene (bis-3-(3-triethoxysilylpropyl)urea)(BSBDA)) organosilica with 1,2-bis(triethoxysilyl) ethane (BTSE) using a co-condensation process. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), nitrogen adsorption-desorption, NMR (proton, 13C and 29Si) spectra, and MALDI-TOF were used to characterise and evaluate the structural properties. The results showed that BSBDA is linked covalently to the mesochannel of the PMO frameworks. The pore size and overall structural properties in the functionalised PMOs were found to depend on the loading amounts of BSBDA. The overall results suggested that the highly functionalised PMOs could be tuned even at high BSBDA loadings (25 wt%).
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Affiliation(s)
- M Abdul Wahab
- Australian Institute for Bioengineering and Nanotechnology (AIBN) (Building 75), The University of Queensland, Brisbane, St Lucia, OLD 4072, Brisbane, St Lucia, QLD 4072, Australia
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Tzeng YY, Zhuo ZY, Lee MY, Liao CS, Wu PC, Huang CJ, Chan MC, Liu TM, Lin YY, Chu SW. Observation of spontaneous polarization misalignments in periodically poled crystals using second-harmonic generation microscopy. Opt Express 2011; 19:11106-11113. [PMID: 21716339 DOI: 10.1364/oe.19.011106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Periodically poled crystal (PPC) is a key component for nonlinear optical applications. Its poling quality relies largely on successful domain inversion and the alignment of spontaneous polarization (SP) vectors in each domain. Here we report the unexpected observation of bulk second harmonic generation (SHG) in PPC when excitation propagating along its optical axis. Based on its tensorial nature, SHG is highly sensitive to the orientation of SP, and therefore the misalignment of SP in each domain of PPC can be revealed noninvasively by SHG microscopy. This nonlinear imaging modality provides optical sectioning capability with 3D sub-micrometer resolution, so it will be useful for in situ investigation of poling quality in PPC.
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Affiliation(s)
- Yu-Yi Tzeng
- Department of Physics, National Taiwan University, Taipei, Taiwan
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33
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Chung CY, Lin YY, Wu KY, Tai WY, Chu SW, Lee YC, Hwu Y, Lee YY. Coherent anti-Stokes Raman scattering microscopy using a single-pass picosecond supercontinuum-seeded optical parametric amplifier. Opt Express 2010; 18:6116-6122. [PMID: 20389633 DOI: 10.1364/oe.18.006116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We have demonstrated coherent anti-Stokes Raman scattering (CARS) microscopy with a single-pass picosecond supercontinuum-seeded optical parametric amplifier (SCOPA). The SCOPA was pumped by a frequency-doubled picosecond passively mode-locked Nd:YVO(4) laser, and was seeded by a supercontinuum light source. Compared with the conventional experimental setups of CARS microscopy, our exposition is substantially simpler because the pump and Stokes lasers are overlapped in the SCOPA automatically and thus steered into a microscope coherently. The feasibility of this novel light source to CARS imaging was illustrated by acquiring the fundamental and overtone CARS images of the aromatic C-H stretching mode of polystyrene beads and an image of the pharynx of a C. elegans of the aliphatic C-H stretching mode.
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Affiliation(s)
- Chao-Yu Chung
- National Synchrotron Radiation Research Center, Hsinchu, Taiwan ROC
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Yu JY, Liao CS, Zhuo ZY, Huang CH, Chui HC, Chu SW. A diffraction-limited scanning system providing broad spectral range for laser scanning microscopy. Rev Sci Instrum 2009; 80:113704. [PMID: 19947734 DOI: 10.1063/1.3254021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Diversified research interests in scanning laser microscopy nowadays require broadband capability of the optical system. Although an all-mirror-based optical design with a suitable metallic coating is appropriate for broad-spectrum applications from ultraviolet to terahertz, most researchers prefer lens-based scanning systems despite the drawbacks of a limited spectral range, ghost reflection, and chromatic aberration. One of the main concerns is that the geometrical aberration induced by off-axis incidence on spherical mirrors significantly deteriorates image resolution. Here, we demonstrate a novel geometrical design of a spherical-mirror-based scanning system in which off-axis aberrations, both astigmatism and coma, are compensated to reach diffraction-limited performance. We have numerically simulated and experimentally verified that this scanning system meets the Marechal condition and provides high Strehl ratio within a 3 degrees x 3 degrees scanning area. Moreover, we demonstrate second-harmonic-generation imaging from starch with our new design. A greatly improved resolution compared to the conventional mirror-based system is confirmed. This scanning system will be ideal for high-resolution linear/nonlinear laser scanning microscopy, ophthalmoscopic applications, and precision fabrications.
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Affiliation(s)
- Jiun-Yann Yu
- Department of Physics, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan
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35
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Tzeng YW, Lin YY, Huang CH, Liu JM, Chui HC, Liu HL, Stone JM, Knight JC, Chu SW. Broadband tunable optical parametric amplification from a single 50 MHz ultrafast fiber laser. Opt Express 2009; 17:7304-9. [PMID: 19399107 DOI: 10.1364/oe.17.007304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We have demonstrated a 0.7 microm - 1.9 microm wavelength-tunable light source based on a single-pass optical parametric amplification (OPA) in a multiperiod magnesium oxide-doped periodically poled lithium niobate crystal. The OPA pump was a frequency-doubled ultrafast ytterbium-doped fiber oscillator, and the residual 1040 nm laser power after frequency doubling was recycled to generate a supercontinuum seeding source. Compared with conventional OPAs, this system is free from timing jitter between the pump laser and the seeding source. Over 50% conversion efficiency was obtained with 10 nJ pump energy. Combined with a 50 MHz repetition rate, this versatile source is ideal for biomedical and spectroscopic applications.
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Affiliation(s)
- Yan-Wei Tzeng
- Department of Physics, National Taiwan University, Taipei, Taiwan, ROC
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36
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Chu SW, Tai SP, Liu TM, Sun CK, Lin CH. Selective imaging in second-harmonic-generation microscopy with anisotropic radiation. J Biomed Opt 2009; 14:010504. [PMID: 19256686 DOI: 10.1117/1.3080722] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
As a novel modality of optical microscopy, second-harmonic generation (SHG) provides attractive features including intrinsic optical sectioning, noninvasiveness, high specificity, and high penetrability. For a biomedical application, the epicollection of backward propagating SHG is necessary. But due to phase-matching constraint, SHG from thick tissues is preferentially forward propagation. Myosin and collagen are two of the most abundant fibrous proteins in vertebrates, and both exhibit a strong second-harmonic response. We find that the radiation patterns of myosin-based muscle fibers and collagen fibrils are distinct due to coherence effects. Based on these asymmetric radiation patterns, we demonstrate selective imaging between intertwining muscle fibers and type I collagen fibrils with forward and backward SHG modalities, respectively. Thick muscle fibers dominate the forward signal, while collagen fibril distribution is preferentially resolved in the backward channel without strong interference from muscle. Moreover, we find that well-formed collagen fibrils are highlighted by forward SHG, while loosely arranged collagen matrix is outlined by backward signal.
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Affiliation(s)
- Shi-Wei Chu
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
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37
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Chan MC, Chu SW, Tseng CH, Wen YC, Chen YH, Su GDJ, Sun CK. Cr:Forsterite-laser-based fiber-optic nonlinear endoscope with higher efficiencies. Microsc Res Tech 2008; 71:559-63. [DOI: 10.1002/jemt.20586] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Huang CH, Lin HY, Lin CH, Chui HC, Lan YC, Chu SW. The phase-response effect of size-dependent optical enhancement in a single nanoparticle. Opt Express 2008; 16:9580-9586. [PMID: 18575525 DOI: 10.1364/oe.16.009580] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We demonstrate detailed simulations and experiments of near-field phase-response in a single silver nanoparticle. The plasmon-photon interaction is directly observed in the vicinity of silver nanoparticles through a near-field scanning optical microscope (NSOM). Our results manifest the correlation of phase-response and size-dependent optical enhancement. Detailed interference behaviors between optical excitation and plasmon mediated re-radiation are revealed on a single particle basis. This observation facilitates nano-applications in controlling the spatial distribution of surface plasmon (SP) modes by means of nanostructures.
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Affiliation(s)
- Chen-Han Huang
- Institute of Electro-Optical Science and Engineering, National Cheng Kung University, No.1, University Road, Tainan 701, Taiwan
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Liu TM, Lee YW, Chang CF, Yeh SC, Wang CH, Chu SW, Sun CK. Imaging polyhedral inclusion bodies of nuclear polyhedrosis viruses with second harmonic generation microscopy. Opt Express 2008; 16:5602-5608. [PMID: 18542664 DOI: 10.1364/oe.16.005602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We studied the polarization anisotropy of second harmonic generation (SHG) in polyhedral inclusion bodies (PIBs) of nuclear polyhedrosis viruses (NPV). Due to a body-centered-cubic arrangement of polyhedrin trimers, a characteristic SHG polarization property with a mixture of I23 and I3 symmetry was measured from PIBs. With this characteristic SHG anisotropy, it provides an intrinsic nonlinear signal for virus infection studies in living cells. With multimodal harmonic generation microscopy, we also demonstrated 3D imaging on PIBs of NPV in living cells. The distribution and the number of PIBs in intact infected cells can be revealed without the help of fluorescent labeling.
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Affiliation(s)
- Tzu-Ming Liu
- Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan, ROC
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Chu SW, Tai SP, Chan MC, Sun CK, Hsiao IC, Lin CH, Chen YC, Lin BL. Thickness dependence of optical second harmonic generation in collagen fibrils. Opt Express 2007; 15:12005-12010. [PMID: 19547564 DOI: 10.1364/oe.15.012005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Simultaneous backward and forward second harmonic generations from isolated type-I collagen matrix are observed. Optical interference behaviors of these nonlinear optical signals are studied with accurately determined fibril thickness by an atomic force microscope. The nonlinear emission directions are strongly dependent on the coherent interaction within and between collagen fibrils. A linear relationship is obtained to estimate collagen fibril thickness with nanometer precision noninvasively by evaluating the forward/backward second harmonic generation ratio.
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Chen SY, Hsieh CS, Chu SW, Lin CY, Ko CY, Chen YC, Tsai HJ, Hu CH, Sun CK. Noninvasive harmonics optical microscopy for long-term observation of embryonic nervous system development in vivo. J Biomed Opt 2006; 11:054022. [PMID: 17092171 DOI: 10.1117/1.2363369] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Nervous system development is a complicated dynamic process, and many mechanisms remain unknown. By utilizing endogenous second-harmonic-generation as the contrast of polarized nerve fibers and third-harmonic-generation (THG) to reveal morphological changes, we have successfully observed the vertebrate embryonic nervous development from the very beginning based on a 1230-nm light source. The dynamic development of the nerve system within a live zebrafish embryo can be recorded continuously more than 20 hr without fluorescence markers. Since the THG process is not limited by the time of gene expression and differentiation as fluorescence-based techniques are, the observable stages can be advanced to the very beginning of the development process. The complete three-dimensional brain development from a neural plate to a neural tube can be uncovered with a submicron lateral resolution. We have, for the first time, also reported the generation of SHG from myelinated nerve fibers and the outer segment of the photoreceptors with a stacked membrane structure. Our study clearly indicates the fact that higher-harmonics-based optical microscopy has the strong potential to long-term in vivo study of the nervous system, including genetic disorders of the nervous system, axon pathfinding, neural regeneration, neural repair, and neural stem cell development.
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Affiliation(s)
- Szu-Yu Chen
- Department of Electrical Engineering and Graduate Institute of Electro-Optical Engineering, National Taiwan University, Taipei 10617, Taiwan
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Chu SW, Chan MC, Tai SP, Keller S, DenBaars SP, Sun CK. Simultaneous four-photon luminescence, third-harmonic generation, and second-harmonic generation microscopy of GaN. Opt Lett 2005; 30:2463-5. [PMID: 16196353 DOI: 10.1364/ol.30.002463] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We demonstrate what is to our knowledge the first example of four-photon luminescence microscopy in GaN and apply it to quality mapping of bulk GaN. The simultaneously acquired second- and third-harmonic generation can be used to map the distribution of the piezoelectric field and the band-tail state density, respectively. Through spectrum- and power-dependent studies, the fourth power dependence of the band edge luminescence is confirmed. The superb spatial resolution of the four-photon luminescence modality is also demonstrated. This technique provides a high-resolution, noninvasive monitoring and tool for examining the physical properties of semiconductors.
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Affiliation(s)
- Shi-Wei Chu
- Graduate Institute of Electro-Optical Engineering, National Taiwan University, Taipei 10617, Taiwan
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Sun CK, Chu SW, Chen SY, Tsai TH, Liu TM, Lin CY, Tsai HJ. Higher harmonic generation microscopy for developmental biology. J Struct Biol 2005; 147:19-30. [PMID: 15109602 DOI: 10.1016/j.jsb.2003.10.017] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2003] [Revised: 10/06/2003] [Indexed: 11/29/2022]
Abstract
Optical higher harmonic generation, including second harmonic generation and third harmonic generation, leaves no energy deposition to its interacted matters due to an energy-conservation characteristic, providing the "noninvasiveness" nature desirable for biological studies. Combined with its nonlinearity, higher harmonic generation microscopy provides excellent three-dimensional (3D) sectioning capability, offering new insights into the studies of embryonic morphological changes and complex developmental processes. By choosing a laser working in the biological penetration window, here we present a noninvasive in vivo light microscopy with sub-micron 3D resolution and millimeter penetration, utilizing endogenous higher harmonic generation signals in live specimens. Noninvasive imaging was performed in live zebrafish (Danio rerio) embryos. The complex developmental processes within > 1-mm-thick zebrafish embryos can be observed in vivo without any treatment. No optical damage was found even with high illumination after long-term observations and the examined embryos all developed normally at least to the larval stage. The excellent 3D resolution of the demonstrated technology allows us to capture the subtle developmental information on the cellular or sub-cellular levels occurring deep inside the live embryos and larvae. This technique can not only provide in vivo observation of the cytoarchitecture dynamics during embryogenesis with submicron resolution and millimeter penetration depth, but would also make strong impact in developmental and structural biology studies.
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Affiliation(s)
- Chi-Kuang Sun
- Graduate Institute of Electro-Optical Engineering and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan, ROC.
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Chu SW, Chen SY, Chern GW, Tsai TH, Chen YC, Lin BL, Sun CK. Studies of chi(2)/chi(3) tensors in submicron-scaled bio-tissues by polarization harmonics optical microscopy. Biophys J 2005; 86:3914-22. [PMID: 15189888 PMCID: PMC1304293 DOI: 10.1529/biophysj.103.034595] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Optical second- and third-harmonic generations have attracted a lot of attention in the biomedical imaging research field recently due to their intrinsic sectioning ability and noninvasiveness. Combined with near-infrared excitation sources, their deep-penetration ability makes these imaging modalities suitable for tissue characterization. In this article, we demonstrate a polarization harmonics optical microscopy, or P-HOM, to study the nonlinear optical anisotropy of the nanometer-scaled myosin and actin filaments inside myofibrils. By using tight focusing we can avoid the phase-matching condition due to micron-scaled, high-order structures in skeletal muscle fibers, and obtain the submicron-scaled polarization dependencies of second/third-harmonic generation intensities on the inclination angle between the long axes of the filaments and the polarization direction of the linear polarized fundamental excitation laser light. From these dependencies, detailed information on the tensor elements of the second/third-order nonlinear susceptibilities contributed from the myosin/actin filaments inside myofibrils can thus be analyzed and obtained, reflecting the detailed arrangements and structures of the constructing biomolecules. By acquiring a whole, nonlinearly sectioned image with a submicron spatial resolution, we can also compare the polarization dependency and calculate the nonlinear susceptibilities over a large area of the tissue at the same time-which not only provides statistical information but will be especially useful with complex specimen geometry.
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Affiliation(s)
- Shi-Wei Chu
- Department of Electrical Engineering and Graduate Institute of Electro-Optical Engineering, National Taiwan University, Taipei, Taiwan, Republic of China
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Abstract
In recent years, nonlinear laser scanning microscopy has gained much attention due to its unique ability of deep optical sectioning. Based on our previous studies, a 1,200-1,300-nm femtosecond laser can provide superior penetration capability with minimized photodamage possibility. However, with the longer wavelength excitation, three-photon-fluorescence (3PF) would be necessary for efficient use of intrinsic and extrinsic visible fluorophores. The three-photon process can provide much better spatial resolution than two-photon-fluorescence due to the cubic power dependency. On the other hand, third-harmonic-generation (THG), another intrinsic three-photon process, is interface-sensitive and can be used as a general structural imaging modality to show the exact location of cellular membranes. The virtual-transition characteristic of THG prevents any excess energy from releasing in bio-tissues and, thus, THG acts as a truly noninvasive imaging tool. Here we demonstrated the first combined 3PF and THG microscopy, which can provide three-dimensional high-resolution images with both functional molecule specificity and sub-micrometer structural mapping capability. The simultaneously acquired 3PF and THG images based on a 1,230-nm Cr:forsterite femtosecond laser are shown with a Hoechst-labeled hepatic cell sample. Strong 3PF around 450 nm from DNA-bounded Hoechst-33258 can be observed inside each nucleus while THG reveals the location of plasma membranes and other membrane-based organelles such as mitochondria. Considering that the maximum-allowable laser power in common nonlinear laser microscopy is less than 10 mW at 800 nm, it is remarkable that even with a 100-mW 1,230-nm incident power, there is no observable photo damage on the cells, demonstrating the noninvasiveness of this novel microscopy technique.
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Affiliation(s)
- Shi-Wei Chu
- Graduate Institute of Electro-Optical Engineering and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan
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Abstract
Because it avoids the in-focus photodamage and phototoxicity problem of two-photon-fluorescence excitation, multiharmonic-generation biopsy based on a 1200-1300-nm light source could provide a truly noninvasive and highly penetrative optical sectioning of skin. We study multiharmonic-generation biopsy of fixed mouse skin. Our preliminary study suggests that this technique could provide submicrometer-resolution deep-tissue noninvasive biopsy images in skin without the use of fluorescence and exogenous markers.
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Affiliation(s)
- Chi-Kuang Sun
- Department of Electrical Engineering and Graduate Institute of Electro-Optical Engineering, National Taiwan University, Taipei 10617, Taiwan.
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Chu SW, Chen SY, Tsai TH, Liu TM, Lin CY, Tsai HJ, Sun CK. In vivo developmental biology study using noninvasive multi-harmonic generation microscopy. Opt Express 2003; 11:3093-9. [PMID: 19471431 DOI: 10.1364/oe.11.003093] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Morphological changes and complex developmental processes inside vertebrate embryos are difficult to observe noninvasively with millimeter-penetration and sub-micrometer-resolution at the same time. By using higher harmonic generation, including second and third harmonics, as the microscopic contrast mechanism, optical noninvasiveness can be achieved due to the virtual-level-transition characteristic. The intrinsic nonlinearity of harmonic generations provides optical sectioning capability while the selected 1230-nm near-infrared light source provides the deeppenetration ability. The complicated development within a ~1.5-mm thick zebrafish (Danio rerio) embryo from initial cell proliferation, gastrulation, to tissue formation can all be observed clearly in vivo without any treatment on the live specimen.
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Chen IH, Chu SW, Bresson F, Tien MC, Shi JW, Sun CK. Three-dimensional electric field visualization utilizing electric-field-induced second-harmonic generation in nematic liquid crystals. Opt Lett 2003; 28:1338-1340. [PMID: 12906082 DOI: 10.1364/ol.28.001338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
An electric-field-induced second-harmonic-generation signal in a nematic liquid crystal is used to map the electric field in an integrated-circuit-like sample. Since the electric-field-induced second-harmonic-generation signal intensity exhibits a strong dependence on the polarization of the incident laser beam, both the amplitude and the orientation of the electric field vectors can be measured. Combined with scanning second-harmonic-generation microscopy, three-dimensional electric field distribution can be easily visualized with high spatial resolution of the order of 1 microm.
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Affiliation(s)
- I-Hsiu Chen
- Department of Electrical Engineering and Graduate Institute of Electro-Optical Engineering, National Taiwan University, Taipei 10617, Taiwan
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Chu SW, Liu TM, Sun CK, Lin CY, Tsai HJ. Real-time second-harmonic-generation microscopy based on a 2-GHz repetition rate Ti:sapphire laser. Opt Express 2003; 11:933-8. [PMID: 19461809 DOI: 10.1364/oe.11.000933] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The problem of weak harmonic generation signal intensity limited by photodamage probability in optical microscopy and spectroscopy could be resolved by increasing the repetition rate of the excitation light source. Here we demonstrate the first photomultiplier-based real-time second-harmonic-generation microscopy taking advantage of the strongly enhanced nonlinear signal from a high-repetition-rate Ti:sapphire laser. We also demonstrate that the photodamage possibility in common biological tissues can be efficiently reduced with this high repetition rate laser at a much higher average power level compared to the commonly used ~80- MHz repetition rate lasers.
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Chu SW, Chen IH, Liu TM, Chen PC, Sun CK, Lin BL. Multimodal nonlinear spectral microscopy based on a femtosecond Cr:forsterite laser. Opt Lett 2001; 26:1909-11. [PMID: 18059734 DOI: 10.1364/ol.26.001909] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We demonstrate a novel multimodal nonlinear spectral microscopy based on a femtosecond Cr:forsterite laser at 1230 nm. By acquiring the whole nonlinear spectrum in the visible and near-NIR region, this novel technique allows a combination of different imaging modalities, including second-harmonic generation, third-harmonic generation, and multiple-photon fluorescence. Combined with the selected excitation wavelength, which is located in the IR transparency window, this microscopic technique can provide high penetration depth with reduced damage and is ideal for studying living cells.
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