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Cao X, Yang H, Wu ZL, Li BB. Ultrasound sensing with optical microcavities. LIGHT, SCIENCE & APPLICATIONS 2024; 13:159. [PMID: 38982066 PMCID: PMC11233744 DOI: 10.1038/s41377-024-01480-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 04/10/2024] [Accepted: 05/13/2024] [Indexed: 07/11/2024]
Abstract
Ultrasound sensors play an important role in biomedical imaging, industrial nondestructive inspection, etc. Traditional ultrasound sensors that use piezoelectric transducers face limitations in sensitivity and spatial resolution when miniaturized, with typical sizes at the millimeter to centimeter scale. To overcome these challenges, optical ultrasound sensors have emerged as a promising alternative, offering both high sensitivity and spatial resolution. In particular, ultrasound sensors utilizing high-quality factor (Q) optical microcavities have achieved unprecedented performance in terms of sensitivity and bandwidth, while also enabling mass production on silicon chips. In this review, we focus on recent advances in ultrasound sensing applications using three types of optical microcavities: Fabry-Perot cavities, π-phase-shifted Bragg gratings, and whispering gallery mode microcavities. We provide an overview of the ultrasound sensing mechanisms employed by these microcavities and discuss the key parameters for optimizing ultrasound sensors. Furthermore, we survey recent advances in ultrasound sensing using these microcavity-based approaches, highlighting their applications in diverse detection scenarios, such as photoacoustic imaging, ranging, and particle detection. The goal of this review is to provide a comprehensive understanding of the latest advances in ultrasound sensing with optical microcavities and their potential for future development in high-performance ultrasound imaging and sensing technologies.
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Affiliation(s)
- Xuening Cao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hao Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zu-Lei Wu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Bei-Bei Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, China.
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Lee Y, Zhang HF, Sun C. Highly sensitive ultrasound detection using nanofabricated polymer micro-ring resonators. NANO CONVERGENCE 2023; 10:30. [PMID: 37338745 DOI: 10.1186/s40580-023-00378-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 06/01/2023] [Indexed: 06/21/2023]
Abstract
Photoacoustic (PA) imaging enables noninvasive volumetric imaging of biological tissues by capturing the endogenous optical absorption contrast. Conventional ultrasound detectors using piezoelectric materials have been widely used for transducing ultrasound signals into the electrical signals for PA imaging reconstruction. However, their inherent limitations in detection bandwidth and sensitivity per unit area have unfortunately constrained the performance of PA imaging. Optical based ultrasound detection methods emerge to offer very promising solutions. In particular, polymer micro-ring resonators (MRRs) in the form of integrated photonic circuits (IPC) enable significant reduction for the sensing area to 80 μm in diameter, while maintaining highly sensitive ultrasound detection with noise equivalent pressure (NEP) of 0.49 Pa and a broad detection frequency range up to 250 MHz. The continued engineering innovation has further transformed MRRs to be transparent to the light and thus, opens up a wide range of applications, including multi-modality optical microscope with isometric resolution, PA endoscope, photoacoustic computed tomography (PACT), and more. This review article summarizes and discusses the evolution of polymer MRR design and the associated nanofabrication process for improving the performance of ultrasound detection. The resulting novel imaging applications will also be reviewed and discussed.
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Affiliation(s)
- Youngseop Lee
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Hao F Zhang
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Cheng Sun
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA.
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Elongated-Hexagonal Photonic Crystal for Buffering, Sensing, and Modulation. NANOMATERIALS 2021; 11:nano11030809. [PMID: 33809856 PMCID: PMC8004163 DOI: 10.3390/nano11030809] [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: 02/20/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 11/17/2022]
Abstract
A paradigm for high buffering performance with an essential fulfillment for sensing and modulation was set forth. Through substituting the fundamental two rows of air holes in an elongated hexagonal photonic crystal (E-PhC) by one row of the triangular gaps, the EPCW is molded to form an irregular waveguide. By properly adjusting the triangle dimension solitary, we fulfilled the lowest favorable value of the physical-size of each stored bit by about μ5.5510 μm. Besides, the EPCW is highly sensitive to refractive index (RI) perturbation attributed to the medium through infiltrating the triangular gaps inside the EPCW by microfluid with high RI sensitivity of about 379.87 nm/RIU. Furthermore, dynamic modulation can be achieved by applying external voltage and high electro-optical (EO) sensitivity is obtained of about 748.407 nm/RIU. The higher sensitivity is attributable to strong optical confinement in the waveguide region and enhanced light-matter interaction in the region of the microfluid triangular gaps inside the EPCW and conventional gaps (air holes). The EPCW structure enhances the interaction between the light and the sensing medium.
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High Figure of Merit Optical Buffering in Coupled-Slot Slab Photonic Crystal Waveguide with Ionic Liquid. NANOMATERIALS 2020; 10:nano10091742. [PMID: 32899131 PMCID: PMC7558017 DOI: 10.3390/nano10091742] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/24/2020] [Accepted: 08/26/2020] [Indexed: 12/01/2022]
Abstract
Slow light with adequate low group velocity and wide bandwidth with a flat band of the zero-dispersion area were investigated. High buffering capabilities were obtained in a silicon-polymer coupled-slot slab photonic crystal waveguide (SP-CS-SPCW) with infiltrating slots by ionic liquid. A figure of merit (FoM) around 0.663 with the lowest physical bit length Lbit of 4.6748 µm for each stored bit in the optical communication waveband was gained by appropriately modifying the square air slot length. Posteriorly, by filling the slots with ionic liquid, the Lbit was enhanced to be 4.2817 μm with the highest FoM of 0.72402 in wider transmission bandwidth and ultra-high bit rate in terabit range, which may become useful for the future 6G mobile communication network. Ionic liquids have had a noticeable effect in altering the optical properties of photonic crystals. A polymer was used for the future incorporation of an electro-optic effect in buffers to realize the dynamic controlling of optical properties. Ionic liquids enhanced the transmission rate through optical materials. Additionally, the delay time in the ns-range was achieved, providing longer delay and ultra-low group velocity, which is important for light-matter interaction in light amplifiers and nonlinear devices.
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Rola K, Zajac A, Czajkowski M, Fiedot-Tobola M, Szpecht A, Cybinska J, Smiglak M, Komorowska K. Electron Beam Patterning of Polymerizable Ionic Liquid Films for Application in Photonics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:11968-11978. [PMID: 31442379 DOI: 10.1021/acs.langmuir.9b00759] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Planar photonic components can be fabricated with high resolution by electron beam patterning of polymer thin films on solid substrates such as silicon and glass. However, polymer films are normally formed by spin-coating lithographic resists containing not only polymers but also volatile solvents, which is a serious environmental and health issue. Therefore, we investigate a new type of material for planar structure fabrication (i.e., room-temperature ionic liquids (RTILs) with a polymerizable allyl group) that is electron-beam-curable, solvent-free, and thus potentially interesting for processing materials with weak resistance to solvents. We fabricate planar polymer microstructures by electron beam patterning of RTIL thin films in vacuum, which is possible because of the negligible volatility of ionic liquids. Three different polymerizable ionic liquids {i.e., [Allmim][Cl] (1-allyl-3-methylimidazolium chloride), [Allmim][NTf2] (1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide), and [Allmmim][NTf2] (1-allyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide)} are compared in terms of the quality of the fabricated microstructures. We demonstrate that the shape of the more viscous RTIL with the Cl- anion is less distorted during electron-beam-activated polymerization than the shape of the less viscous RTILs with a large NTf2- anion. Furthermore, the surface tension of the NTf2-based ionic liquid decreases significantly with temperature as compared to that of the Cl-based ionic liquid. Thus, we suggest that the thermocapillary effect, that is, the Marangoni flow caused by a temperature gradient, might be responsible for the differences in the shape of the RTIL-derived microstructures. Also, we analyze the chemistry of the electron-beam-activated polymerization of RTIL by the use of Fourier-transform infrared spectroscopy (FTIR) and conclude that because of the disappearance of C═C bonds the free radical polymerization is a probable reaction mechanism. Finally, we show that polymerized microstructures are potentially attractive as planar photonic components because of good optical properties such as a high refractive index.
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Affiliation(s)
- Krzysztof Rola
- ŁUKASIEWICZ Research Network - PORT Polish Center for Technology Development , Stablowicka 147 Str , 54-066 Wroclaw , Poland
| | - Adrian Zajac
- Material Synthesis Group, Poznan Science and Technology Park , ul. Rubiez 46 , 61-612 Poznan , Poland
| | - Maciej Czajkowski
- ŁUKASIEWICZ Research Network - PORT Polish Center for Technology Development , Stablowicka 147 Str , 54-066 Wroclaw , Poland
| | - Marta Fiedot-Tobola
- ŁUKASIEWICZ Research Network - PORT Polish Center for Technology Development , Stablowicka 147 Str , 54-066 Wroclaw , Poland
| | - Andrea Szpecht
- Material Synthesis Group, Poznan Science and Technology Park , ul. Rubiez 46 , 61-612 Poznan , Poland
- Faculty of Chemistry , Adam Mickiewicz University , Umultowska 89B , 61-614 Poznan , Poland
| | - Joanna Cybinska
- ŁUKASIEWICZ Research Network - PORT Polish Center for Technology Development , Stablowicka 147 Str , 54-066 Wroclaw , Poland
- Faculty of Chemistry , University of Wroclaw , 14 F. Joliot-Curie Str . 50-383 Wroclaw , Poland
| | - Marcin Smiglak
- Material Synthesis Group, Poznan Science and Technology Park , ul. Rubiez 46 , 61-612 Poznan , Poland
| | - Katarzyna Komorowska
- ŁUKASIEWICZ Research Network - PORT Polish Center for Technology Development , Stablowicka 147 Str , 54-066 Wroclaw , Poland
- Department of Optics and Photonics, Faculty of Fundamental Problems of Technology , Wroclaw University of Science and Technology , 27 Wybrzeze Wyspianskiego Str ., 50-370 Wroclaw , Poland
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Prorok S, Petrov AY, Eich M, Luo J, Jen AKY. Trimming of high-Q-factor silicon ring resonators by electron beam bleaching. OPTICS LETTERS 2012; 37:3114-3116. [PMID: 22859103 DOI: 10.1364/ol.37.003114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We demonstrate a novel position-resolved resonance trimming strategy for silicon ring resonators. Ring resonators are covered with a chromophore-doped guest host polymer cladding. Illumination of the polymer cladding with high-energy electrons causes a bleaching of the chromophore molecules. Bleaching of the chromophores induces a reduction of the polymer refractive index, which can be used to trim the resonance frequency of the ring resonators. A maximum refractive index change of 0.06 and a TM polarization resonance shift of 16.4 nm have been measured. A Q factor of 20,000 before bleaching remains unaltered after the electron beam exposure process.
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Affiliation(s)
- Stefan Prorok
- Institute of Optical and Electronic Materials, Hamburg University of Technology, Hamburg, Germany. stefan.prorok@tu‑harburg.de
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Ling T, Chen SL, Guo LJ. Fabrication and characterization of high Q polymer micro-ring resonator and its application as a sensitive ultrasonic detector. OPTICS EXPRESS 2011; 19:861-9. [PMID: 21263625 PMCID: PMC3368304 DOI: 10.1364/oe.19.000861] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 12/18/2010] [Accepted: 12/23/2010] [Indexed: 05/19/2023]
Abstract
Smooth sidewall silicon micro-ring molds have been fabricated using resist reflow and thermal oxidation method. High Q factor polymer micro-ring resonators have been fabricated using these molds. Quality factors as high as 10(5) have been measured at telecommunication wavelength range. By carefully examining the different loss mechanisms in polymer micro-ring, we find that the surface scattering loss can be as low as 0.23 dB/cm, much smaller than the absorption loss of the polystyrene polymer used in our devices. When used as an ultrasound detector such a high Q polymer micro-ring device can achieve an acoustic sensitivity around 36.3 mV/kPa with 240 μW operating power. A noise equivalent pressure (NEP) is around 88 Pa over a bandwidth range of 1-75 MHz. We have improved the NEP by a factor of 3 compared to our previous best result.
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Dalton LR, Sullivan PA, Bale DH. Electric Field Poled Organic Electro-optic Materials: State of the Art and Future Prospects. Chem Rev 2009; 110:25-55. [DOI: 10.1021/cr9000429] [Citation(s) in RCA: 777] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Larry R. Dalton
- Department of Chemistry, University of Washington, Seattle, Washington 98195
| | - Philip A. Sullivan
- Department of Chemistry, University of Washington, Seattle, Washington 98195
| | - Denise H. Bale
- Department of Chemistry, University of Washington, Seattle, Washington 98195
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