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Nanoengineering of conductively coupled metallic nanoparticles towards selective resonance modes within the near-infrared regime. Sci Rep 2022; 12:7829. [PMID: 35550525 PMCID: PMC9098514 DOI: 10.1038/s41598-022-11539-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 04/08/2022] [Indexed: 11/08/2022] Open
Abstract
In this work, the mode transition effect of different plasmonic resonances in linked dimers by a conductive junction is numerically investigated.Without the junction, the dimer supports a single dipolar bonding plasmon mode, while two new resonance modes, a screened bonding dipolar mode and a low energy charge transfer plasmon mode, emerge when two nanoparticles are linked via a bridge. Such effect is proved to be unrelated to the shape of the nanoparticles, whether sphere, core-shell or nanoegg. However, it was found that the status of each specific resonance mode is profoundly influenced by the shape of nanoparticles. Furthermore, a detailed discussion of mechanisms of controlling plasmon modes, specially charge transfer mode, and tuning their corresponding spectra in bridged nanoparticles as functions of nanoparticle parameters and junction conductance is presented. These results show that the optical response of the dimer is highly sensitive to changes in the inter-particle gap. While the capacitive dimer provides a strong hotstop, the conductive dimer leads to highly controllable low energy plasmon mode at the mid-infrared region appropriate for novel applications. These findings may serve as an important guide for optical properties of linked nanoparticles as well as understanding the transition between the capacitive and conductive coupling.
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2
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Surface Plasmon Resonance of Large-Size Ag Nanobars. MICROMACHINES 2022; 13:mi13040638. [PMID: 35457942 PMCID: PMC9025477 DOI: 10.3390/mi13040638] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/07/2022] [Accepted: 04/12/2022] [Indexed: 02/04/2023]
Abstract
Silver nanobars have attracted much attention due to their distinctive localized surface plasmon resonance (LSPR) in the visible and near-infrared regions. In this work, large-size Ag nanobars (length: 400~1360 nm) working at a longer-wavelength near-infrared range (>1000 nm) have been synthesized. By using the finite-difference time-domain (FDTD) simulation, the LSPR properties of a single large-size Ag nanobar are systematically investigated. The LSPR in Ag nanobar can be flexibly tuned in a wide wavelength range (400~2000 nm) by changing the bar length or etching the bar in the length direction. Our work provides a flexible way to fabricate nanoparticle arrays using large-size nanobars and throws light on the applications of large-size nanomaterials on wide spectral absorbers, LSPR-based sensors and nanofilters.
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3
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Chau YFC, Chang HE, Huang PS, Wu PC, Lim CM, Chiang LM, Wang TJ, Chao CTC, Kao TS, Shih MH, Chiang HP. Enhanced photoluminescence and shortened lifetime of DCJTB by photoinduced metal deposition on a ferroelectric lithography substrate. Sci Rep 2022; 12:6173. [PMID: 35418622 PMCID: PMC9007977 DOI: 10.1038/s41598-022-10303-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/30/2022] [Indexed: 11/09/2022] Open
Abstract
The photodeposition of metallic nanostructures onto ferroelectric surfaces could enable new applications based on the assembly of molecules and patterning local surface reactivity by enhancing surface field intensity. DCJTB (4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran) is an excellent fluorescent dye and dopant material with a high quantum efficiency used for OLED displays on the market. However, how to raise the photoluminescence (PL) and reduce the lifetime of DCJTB in a substrate remain extraordinary challenges for its application. Here, we demonstrate a tunable ferroelectric lithography plasmon-enhanced substrate to generate photo-reduced silver nanoparticles (AgNPs) and achieve enhanced PL with a shortened lifetime depending on the substrate's annealing time. The enhanced PL with shortened lifetimes can attribute to the localized electromagnetic (EM) wave produced by the nanotextured AgNPs layers' surface and gap plasmon resonances. The simulation is based on the three-dimensional finite element method to explain the mechanism of experimental results. Since the absorption increases, the remarkable enhanced PL of DCJTB can attain in the fabricated periodically proton exchanged (PPE) lithium niobate (LiNbO3) substrate. Furthermore, the proposed fabrication method demonstrates to help tune the surface EM wave distribution in the substrate, which can simultaneously achieve the significantly shortened lifetime and high PL intensity of DCJTB in the substrate. Compared with the un-annealed substrate, the PL intensity of DCJTB in the assembly metallic nanostructures is enhanced 13.70 times, and the PL's lifetime is reduced by 12.50%, respectively. Thus, the fabricated substrate can be a promising candidate, verifying chemically patterned ferroelectrics' satisfaction as a PL-active substrate.
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Affiliation(s)
- Yuan-Fong Chou Chau
- Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Tungku Link, Gadong, BE1410, Brunei Darussalam
| | - Hao-En Chang
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 202, Taiwan, ROC
| | - Po-Sheng Huang
- Department of Photonics, National Cheng Kung University, Tainan, 70101, Taiwan, ROC
| | - Pin Chieh Wu
- Department of Photonics, National Cheng Kung University, Tainan, 70101, Taiwan, ROC
| | - Chee Ming Lim
- Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Tungku Link, Gadong, BE1410, Brunei Darussalam
| | - Li-Ming Chiang
- Department of Photonics & Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, 300, Taiwan, ROC
| | - Tzyy-Jiann Wang
- Institute of Electro-Optical Engineering, National Taipei University of Technology, Taipei, 10608, Taiwan, ROC
| | - Chung-Ting Chou Chao
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 202, Taiwan, ROC
| | - Tsung Sheng Kao
- Department of Photonics & Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Chiao Tung University, Hsinchu, 300, Taiwan, ROC
| | - Min-Hsiung Shih
- Research Center for Applied Sciences, Academia Sinica, Taipei, 11529, Taiwan, ROC
| | - Hai-Pang Chiang
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 202, Taiwan, ROC.
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Effect of Ultrafast Broadband Nonlinear Optical Responses by Doping Silver into Ti3C2 Nanosheets at Visible Spectra. COATINGS 2022. [DOI: 10.3390/coatings12020189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Ti3C2 nanosheet is a newly discovered two-dimensional (2D) clan. It turns out to have encouraging applications for electromagnetic shielding and energy storage. Here, Ag@ Ti3C2 hybrids are precisely synthesized by using the one-step solution processing method. Also, their ultrafast broadband nonlinear optical responses in the visible region are studied systematically through nanosecond open-aperture Z-scan and transient absorption techniques. The mechanism of two-photon absorption (TPA) is disclosed in the visible region (409–532 nm). When the laser energy is low and the wavelength is longer than 400 nm, nonlinear absorption cannot happen. Meanwhile, as the laser energy increases, two photons will be absorbed by the electrons in the valence band and the electrons will jump to the conduction band. The process is named as two-photon absorption which will make the specimen show reverse saturable absorption (RSA) properties. What is more, the ultrafast carrier dynamics of the specimen are studied by using the transient absorption. The result shows that the decay contains two phases: the fast and then the slow one. The two phases first come from electron–phonon and then from phonon–phonon interactions, respectively. The electron transfer and charge carrier trapping processes are further verified by the outcomes of similar measurements on Ag@ Ti3C2 hybrids. Besides, the two decay processes increase together with the pump fluence. These results show that Ti3C2 nanosheet has potential applications in broadband optical limiter.
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Chou Chau YF, Chou Chao CT, Huang HJ, Chen SH, Kao TS, Chiang HP. A multichannel color filter with the functions of optical sensor and switch. Sci Rep 2021; 11:22910. [PMID: 34824366 PMCID: PMC8617143 DOI: 10.1038/s41598-021-02453-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/10/2021] [Indexed: 11/09/2022] Open
Abstract
This paper reports a multichannel color filter with the functions of optical sensor and switch. The proposed structure comprises a metal-insulator-metal (MIM) bus waveguide side-couples to six circular cavities with different sizes for filtering ultra-violet and visible lights into individual colors in the wavelength range of 350-700 nm. We used the finite element method to analyze the electromagnetic field distributions and transmittance properties by varying the structural parameters in detail. The designed plasmonic filter takes advantage of filtering out different colors since the light-matter resonance and interference between the surface plasmon polaritons (SPPs) modes within the six cavities. Results show that the designed structure can preferentially select the desired colors and confine the SPPS modes in one of the cavities. This designed structure can filter eleven color channels with a small full width at half maximum (FWHM) ~ 2 nm. Furthermore, the maximum values of sensitivity, figure of merit, quality factor, dipping strength, and extinction ratio can achieve of 700 nm/RIU, 350 1/RIU, 349.0, 65.04%, and 174.50 dB, respectively, revealing the excellent functions of sensor performance and optical switch, and offering a chance for designing a beneficial nanophotonic device.
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Affiliation(s)
- Yuan-Fong Chou Chau
- Centre for Advanced Material and Energy Sciences, Universiti Brunei Darussalam, Tungku Link, Gadong, BE1410, Brunei Darussalam.
| | - Chung-Ting Chou Chao
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan, ROC
| | - Hung Ji Huang
- Taiwan Instrument Research Institute, National Applied Research Laboratories, Hsinchu, 300, Taiwan, ROC
| | - Sy-Hann Chen
- Department of Electrophysics, National Chiayi University, 600, Chiayi, Taiwan, ROC
| | - Tsung Sheng Kao
- Department of Photonics & Institute of Electro-Optical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu, 300, Taiwan, ROC.
| | - Hai-Pang Chiang
- Department of Optoelectronics and Materials Technology, National Taiwan Ocean University, Keelung, 20224, Taiwan, ROC.
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Nonenzymatic Hydrogen Peroxide Detection Using Surface-Enhanced Raman Scattering of Gold-Silver Core-Shell-Assembled Silica Nanostructures. NANOMATERIALS 2021; 11:nano11102748. [PMID: 34685187 PMCID: PMC8540490 DOI: 10.3390/nano11102748] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 11/23/2022]
Abstract
Hydrogen peroxide (H2O2) plays important roles in cellular signaling and in industry. Thus, the accurate detection of H2O2 is critical for its application. Unfortunately, the direct detection of H2O2 by surface-enhanced Raman spectroscopy (SERS) is not possible because of its low Raman cross section. Therefore, the detection of H2O2 via the presence of an intermediary such as 3,3,5,5-tetramethylbenzidine (TMB) has recently been developed. In this study, the peroxidase-mimicking activity of gold–silver core–shell-assembled silica nanostructures (SiO2@Au@Ag alloy NPs) in the presence of TMB was investigated using SERS for detecting H2O2. In the presence of H2O2, the SiO2@Au@Ag alloy catalyzed the conversion of TMB to oxidized TMB, which was absorbed onto the surface of the SiO2@Au@Ag alloy. The SERS characteristics of the alloy in the TMB–H2O2 mixture were investigated. The evaluation of the SERS band to determine the H2O2 level utilized the SERS intensity of oxidized TMB bands. Moreover, the optimal conditions for H2O2 detection using SiO2@Au@Ag alloy included incubating 20 µg/mL SiO2@Au@Ag alloy NPs with 0.8 mM TMB for 15 min and measuring the Raman signal at 400 µg/mL SiO2@Au@Ag alloy NPs.
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Tathfif I, Yaseer AA, Rashid KS, Sagor RH. Metal-insulator-metal waveguide-based optical pressure sensor embedded with arrays of silver nanorods. OPTICS EXPRESS 2021; 29:32365-32376. [PMID: 34615309 DOI: 10.1364/oe.439974] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/10/2021] [Indexed: 06/13/2023]
Abstract
An optical Metal-Insulator-Metal (MIM) pressure sensor loaded with arrays of silver nanorods (NRs) is proposed in this article. The illustrated sensor contains a straight waveguide coupled with a ladder-shaped resonator. The spectral profile of the proposed schematic is numerically analyzed utilizing the 2D Finite Element Method (FEM). When pressure is exerted upon the silver layer, the resonating area deforms and shifts the resonant wavelength. Extensive computations demonstrate that increasing the deformation shifts the resonant wavelength to the right, establishing a linear relationship. The suggested structure reports maximum pressure sensitivity of 25.4 nm/MPa. Moreover, the impact of NRs on pressure sensitivity is extensively investigated and the results indicate that the designed layout is sensitive to the size and radius of NRs, making it highly tunable. All these features make the modeled prototype a promising nanoscale solution in different fields of engineering.
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Matveeva K, Zyubin A, Demishkevich E, Rafalskiy V, Moiseeva E, Kon I, Kundalevich A, Butova V, Samusev I. Spectral and time-resolved photoluminescence of human platelets doped with platinum nanoparticles. PLoS One 2021; 16:e0256621. [PMID: 34469464 PMCID: PMC8409683 DOI: 10.1371/journal.pone.0256621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/10/2021] [Indexed: 11/19/2022] Open
Abstract
This paper describes a detailed study of spectral and time-resolved photoprocesses in human platelets and their complexes with platinum (Pt) nanoparticles (NPs). Fluorescence, quantum yield, and platelet amino acid lifetime changes in the presence and without femtosecond ablated platinum NPs have been studied. Fluorescence spectroscopy analysis of main fluorescent amino acids and their residues (tyrosine (Tyr), tryptophan (Trp), and phenylalanine (Phe)) belonging to the platelet membrane have been performed. The possibility of energy transfer between Pt NPs and the platelet membrane has been revealed. Förster Resonance Energy Transfer (FRET) model was used to perform the quantitative evaluation of energy transfer parameters. The prospects of Pt NPs usage deals with quenching-based sensing for pathology's based on platelet conformations as cardiovascular diseases have been demonstrated.
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Affiliation(s)
- Karina Matveeva
- REC «Fundamental and Applied Photonics, Nanophotonics», Immanuel Kant Baltic Federal University, Kaliningrad, Kaliningrad region, Russia
| | - Andrey Zyubin
- REC «Fundamental and Applied Photonics, Nanophotonics», Immanuel Kant Baltic Federal University, Kaliningrad, Kaliningrad region, Russia
| | - Elizaveta Demishkevich
- REC «Fundamental and Applied Photonics, Nanophotonics», Immanuel Kant Baltic Federal University, Kaliningrad, Kaliningrad region, Russia
| | - Vladimir Rafalskiy
- REC «Fundamental and Applied Photonics, Nanophotonics», Immanuel Kant Baltic Federal University, Kaliningrad, Kaliningrad region, Russia
| | - Ekaterina Moiseeva
- REC «Fundamental and Applied Photonics, Nanophotonics», Immanuel Kant Baltic Federal University, Kaliningrad, Kaliningrad region, Russia
| | - Igor Kon
- REC «Fundamental and Applied Photonics, Nanophotonics», Immanuel Kant Baltic Federal University, Kaliningrad, Kaliningrad region, Russia
| | - Anna Kundalevich
- REC «Fundamental and Applied Photonics, Nanophotonics», Immanuel Kant Baltic Federal University, Kaliningrad, Kaliningrad region, Russia
| | - Viktoria Butova
- REC «Fundamental and Applied Photonics, Nanophotonics», Immanuel Kant Baltic Federal University, Kaliningrad, Kaliningrad region, Russia
| | - Ilia Samusev
- REC «Fundamental and Applied Photonics, Nanophotonics», Immanuel Kant Baltic Federal University, Kaliningrad, Kaliningrad region, Russia
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A rational design of multimodal asymmetric nanoshells as efficient tunable absorbers within the biological optical window. Sci Rep 2021; 11:15115. [PMID: 34302000 PMCID: PMC8302719 DOI: 10.1038/s41598-021-94409-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 07/12/2021] [Indexed: 11/10/2022] Open
Abstract
In this work, the optical properties of asymmetric nanoshells with different geometries are comprehensively investigated in the quasi-static regime by applying the dipolar model and effective medium theory. The plasmonic behaviors of these nanostructures are explained by the plasmon hybridization model. Asymmetric hybrid nanoshells, composed of off-center core or nanorod core surrounded by a spherical metallic shell layer possess highly geometrically tunable optical resonances in the near-infrared regime. The plasmon modes of this nanostructures arise from the hybridization of the cavity and solid plasmon modes at the inner and outer surfaces of the shell. The results reveal that the symmetry breaking drastically affects the strength of hybridization between plasmon modes, which ultimately affects the absorption spectrum by altering the number of resonance modes, their wavelengths and absorption efficiencies. Therefore, offsetting the spherical core as well as changing the internal geometry of the nanoparticle to nanorod not only shift the resonance frequencies but can also strongly modify the relative magnitudes of the absorption efficiencies. Furthermore, higher order multipolar plasmon modes can appear in the spectrum of asymmetric nanoshell, especially in nanoegg configuration. The results also indicate that the strength of hybridization strongly depends on the metal of shell, material of core and the filling factor. Using Au-Ag alloy as a material of the shell can provide red-shifted narrow resonance peak in the near-infrared regime by combining the specific features of gold and silver. Moreover, inserting a high permittivity core in a nanoshell corresponds to a red-shift, while a core with small dielectric constant results in a blue-shift of spectrum. We envision that this research offers a novel perspective and provides a practical guideline in the fabrication of efficient tunable absorbers in the nanoscale regime.
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Measurement of Low Concentration of Micro-Plastics by Detection of Bioaffinity-Induced Particle Retention Using Surface Plasmon Resonance Biosensors. BIOSENSORS-BASEL 2021; 11:bios11070219. [PMID: 34356691 PMCID: PMC8301956 DOI: 10.3390/bios11070219] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 06/25/2021] [Accepted: 06/30/2021] [Indexed: 12/02/2022]
Abstract
The issue of micro-plastics is becoming more and more important due to their ubiquity and the harm they cause to the human body. Therefore, evaluating the biological–physical interaction of micro-plastics with health cells has become the focus of many research efforts. This study focuses on the movement mode and low concentration detection development for micro-plastics in surface plasmon resonance (SPR). Firstly, 20-micrometer micro-plastics were prepared by grinding and filtering, and the movement mode was explored; then, the characteristics were investigated by SPR. Chromatographic analysis showed that the surface charge of micro-plastics dominated the elution time, and estrogen receptors (ERs) played a supporting role. A difference of micro-plastics in SPR sensorgram was observed, inferring the micro-plastics’ movement in rolling mode on the ERs. Characteristics analysis indicated that the low particle number of micro-plastics on SPR showed a linear relationship with the response unit (RU). When ERs were immobilized on the biosensor, the force of the binding of micro-plastics to ERs under an ultra-low background was equivalent to the dissociation rate constant shown as follows: PS (0.05 nM) > PVC (0.09 nM) > PE (0.14 nM). The ELISA-like magnetic beads experiment verified the specificity between ERs and micro-plastics. Therefore, by using the SPR technique, a biological-derived over-occupation of PS was found via higher binding force with ERs and longer retention time. In the future, there will be considerable potential for micro-plastics issues, such as identification in natural samples, biomarking, real-time detection in specific environments/regions and human health subject.
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Wang P, Chen N, Tang C, Chen J, Liu F, Sheng S, Yan B, Sui C. Engineering the Complex-Valued Constitutive Parameters of Metamaterials for Perfect Absorption. NANOSCALE RESEARCH LETTERS 2017; 12:276. [PMID: 28420225 PMCID: PMC5394092 DOI: 10.1186/s11671-017-2048-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 04/05/2017] [Indexed: 05/03/2023]
Abstract
We theoretically studied how to directly engineer the constitutive parameters of metamaterials for perfect absorbers of electromagnetic waves. As an example, we numerically investigated the necessary refractive index n and extinction coefficient k and the relative permittivity ε and permeability μ of a metamaterial anti-reflection layer, which could cancel the reflection from a hydrogenated amorphous silicon (α-Si:H) thin film on a metal substrate, within the visible wavelength range from 300 to 800 nm. We found that the metamaterial anti-reflection layer should have a negative refractive index (n < 0) for short-wavelength visible light but have a positive refractive index (n > 0) for long-wavelength visible light. The relative permittivity ε and permeability μ could be fitted by the Lorentz model, which exhibited electric and magnetic resonances, respectively.
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Affiliation(s)
- Pengwei Wang
- Center for Optics & Optoelectronics Research, Department of Applied Physics, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Naibo Chen
- Center for Optics & Optoelectronics Research, Department of Applied Physics, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Chaojun Tang
- Center for Optics & Optoelectronics Research, Department of Applied Physics, Zhejiang University of Technology, Hangzhou, 310023, China.
| | - Jing Chen
- College of Electronic Science and Engineering, Nanjing University of Posts and Telecommunications, Nanjing, 210023, China.
- National Laboratory of Solid State Microstructures, Nanjing University, Nanjing, 210093, China.
| | - Fanxin Liu
- Center for Optics & Optoelectronics Research, Department of Applied Physics, Zhejiang University of Technology, Hangzhou, 310023, China
- National Laboratory of Solid State Microstructures, Nanjing University, Nanjing, 210093, China
| | - Saiqian Sheng
- Center for Optics & Optoelectronics Research, Department of Applied Physics, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Bo Yan
- Center for Optics & Optoelectronics Research, Department of Applied Physics, Zhejiang University of Technology, Hangzhou, 310023, China
| | - Chenghua Sui
- Center for Optics & Optoelectronics Research, Department of Applied Physics, Zhejiang University of Technology, Hangzhou, 310023, China
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Ma H, Liang B, Zhuang S, Niu J, Chen J. Study on focusing of subwavelength imaging of a point source based on two-dimensional photonic crystals. OPTICS LETTERS 2017; 42:4012-4015. [PMID: 28957185 DOI: 10.1364/ol.42.004012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 07/25/2017] [Indexed: 06/07/2023]
Abstract
A new focusing structure is proposed, consisting of periodic array air holes in silicon and based on two-dimensional (2D) photonic crystal (PC) with negative refraction and subwavelength imaging characteristics. The light radiating from a point source can form a subwavelength imaging of which the half-width reaches 0.47λ through a wedge PC. Due to the influence of the aberration and evanescent field, the symmetry plane of the image is inside the structure rather than the boundary. In addition, moving the PC by 2 μm to the left horizontally, the image moves by 3.57 μm and the half-width of each image is less than the half-wavelength in this process.
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Xiao TH, Zhao Z, Zhou W, Takenaka M, Tsang HK, Cheng Z, Goda K. Mid-infrared germanium photonic crystal cavity. OPTICS LETTERS 2017; 42:2882-2885. [PMID: 28957198 DOI: 10.1364/ol.42.002882] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 06/29/2017] [Indexed: 06/07/2023]
Abstract
The mid-infrared (MIR) spectral range holds significant potential for spectroscopic and sensing applications because it encompasses the fingerprint region that unveils the vibrational and rotational signatures of molecules. CMOS-compatible on-chip devices that can achieve strong light-matter interaction in the entire fingerprint region are considered a promising way for such applications, but remain unprecedented. Here we present an on-chip MIR germanium photonic crystal cavity that covers the entire fingerprint region. This is made possible by harnessing a homemade air-cladding germanium platform. Our MIR device creates a new avenue toward integrated nonlinear optics and on-chip biochemical sensing in the fingerprint region.
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