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Focusing light into scattering media with ultrasound-induced field perturbation

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Light(Science & Applications) 2021年第9期10卷 1702-1713页

作者： Zhongtao Cheng lihong v.wang Caltech Optical Imaging Laboratory Andrew and Peggy Cherng Department of Medical EngineeringDepartment of Electrical EngineeringCalifornia Institute of TechnologyPasadenaCA91125USA

Focusing light into scattering media,although challenging,is highly desirable in many *** the invention of time-reversed ultrasonically encoded(TRUE)optical focusing,acousto-optic modulation was demonstrated as a promising guidestar mechanism for achieving noninvasive and addressable optical focusing into scattering ***,we report a new ultrasound-assisted technique,ultrasound-induced field perturbation optical focusing,abbreviated as *** in conventional TRUE optical focusing,where only the weak frequency-shifted first-order diffracted photons due to acousto-optic modulation are useful,here UFP leverages the brighter zeroth-order photons diffracted by an ultrasonic guidestar as information carriers to guide optical *** find that the zeroth-order diffracted photons,although not frequency-shifted,do have a field perturbation caused by the existence of the ultrasonic *** detecting and time-reversing the differential field of the frequency-unshifted photons when the ultrasound is alternately ON and OFF,we can focus light to the position where the field perturbation occurs inside the scattering *** demonstrate here that UFP optical focusing has superior performance to conventional TRUE optical focusing,which benefits from the more intense zeroth-order *** further show that UFP optical focusing can be easily and flexibly developed into double-shot realization or even single-shot realization,which is desirable for high-speed wavefront *** new method upsets conventional thinking on the utility of an ultrasonic guidestar and broadens the horizon of light control in scattering *** hope that it provides a more efficient and flexible mechanism for implementing ultrasound-guided wavefront shaping.

关键词： perturbation media realization

Recent Advances in Photoacoustic Tomography

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Biomedical Engineering Frontiers 2021年第1期2卷 27-43页

作者： Lei Li lihong v.wang Caltech Optical Imaging Laboratory Andrew and Peggy Cherng Department of Medical EngineeringDepartment of Electrical EngineeringCalifornia Institute of Technology1200 East California BoulevardMail Code 138-78PasadenaCA 91125USA

Photoacoustic tomography(PAT)that integrates the molecular contrast of optical imaging with the high spatial resolution of ultrasound imaging in deep tissue has widespread applications in basic biological science,preclinical research,and clinical ***,tremendous progress has been made in PAT regarding technical innovations,preclinical applications,and clinical ***,we selectively review the recent progresses and advances in PAT,including the development of advanced PAT systems for small-animal and human imaging,newly engineered optical probes for molecular imaging,broad-spectrum PAT for label-free imaging of biological tissues,high-throughput snapshot photoacoustic topography,and integration of machine learning for image reconstruction and *** envision that PAT will have further technical developments and more impactful applications in biomedicine.

关键词： clinical topography integrate

Single-shot real-time femtosecond imaging of temporal focusing

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Light(Science & Applications) 2018年第1期7卷 593-602页

作者： Jinyang Liang Liren Zhu lihong v.wang Caltech Optical Imaging Laboratory Andrew and Peggy Cherng Department of Medical EngineeringDepartment of Electrical EngineeringCalifornia Institute of Technology1200 East California BoulevardMail Code 138-78PasadenaCA 91125USA Present address:CentreÉnergie Matériaux Télécommunications Institut National de la Recherche Scientifique1650 Boulevard Lionel-BouletVarennesQC J3X1S2Canada

While the concept of focusing usually applies to the spatial domain,it is equally applicable to the time *** imaging of temporal focusing of single ultrashort laser pulses is of great significance in exploring the physics of the space–time duality and finding diverse *** drastic changes in the width and intensity of an ultrashort laser pulse during temporal focusing impose a requirement for femtosecond-level exposure to capture the instantaneous light patterns generated in this exquisite *** far,established ultrafast imaging techniques either struggle to reach the desired exposure time or require repeatable *** have developed single-shot 10-trillion-frame-per-second compressed ultrafast photography(T-CUP),which passively captures dynamic events with 100-fs frame intervals in a single camera *** synergy between compressed sensing and the Radon transformation empowers T-CUP to significantly reduce the number of projections needed for reconstructing a high-quality three-dimensional spatiotemporal *** the only currently available real-time,passive imaging modality with a femtosecond exposure time,T-CUP was used to record the first-ever movie of nonrepeatable temporal focusing of a single ultrashort laser pulse in a dynamic scattering medium.T-CUP’s unprecedented ability to clearly reveal the complex evolution in the shape,intensity,and width of a temporally focused pulse in a single measurement paves the way for single-shot characterization of ultrashort pulses,experimental investigation of nonlinear light-matter interactions,and real-time wavefront engineering for deep-tissue light focusing.

关键词： ultrashort passive scattering

Harnessing a multi-dimensional fibre laser using genetic wavefront shaping

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Light(Science & Applications) 2020年第1期9卷 593-602页

作者： Xiaoming Wei Joseph C.Jing Yuecheng Shen lihong v.wang Caltech Optical Imaging Laboratory Andrew and Peggy Cherng Department of Medical EngineeringDepartment of Electrical EngineeringCalifornia Institute of Technology1200 East California Boulevard MailCode 138-78Pasadena 91125 CAUSA School of Physics and Optoelectronics/State Key Laboratory of Luminescent Materials and Devices/Guangdong Engineering Technology Research and Development Center of Special Optical Fiber Materials and Devices/Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques South China University of Technology381 Wushan RoadGuangzhou 510640China School of Electronics and Information Technology Sun Yatsen UniversityGuangzhou 510006China

The multi-dimensional laser is a fascinating platform not only for the discovery and understanding of new higherdimensional coherent lightwaves but also for the frontier study of the complex three-dimensional(3D)nonlinear dynamics and solitary waves widely involved in physics,chemistry,biology and materials *** controlling coherent lightwave oscillation in multi-dimensional lasers,however,is challenging and has largely been unexplored;yet,it is crucial for both designing 3D coherent light fields and unveiling any underlying nonlinear ***,for the first time,we genetically harness a multi-dimensional fibre laser using intracavity wavefront shaping technology such that versatile lasing characteristics can be *** demonstrate that the output power,mode profile,optical spectrum and mode-locking operation can be genetically optimized by appropriately designing the objective function of the genetic *** is anticipated that this genetic and systematic intracavity control technology for multi-dimensional lasers will be an important step for obtaining high-performance 3D lasing and presents many possibilities for exploring multi-dimensional nonlinear dynamics and solitary waves that may enable new applications.

关键词： fibre dimensional coherent

In vivo superresolution photoacoustic computed tomography by localization of single dyed droplets

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Light(Science & Applications) 2019年第1期8卷 884-892页

作者： Pengfei Zhang Lei Li Li Lin Junhui Shi lihong v.wang Optical Imaging Laboratory Department of Biomedical EngineeringWashington University in St.LouisSt.LouisMissouri 63130USA Caltech Optical Imaging Laboratory Andrew and Peggy Cherng Department of Medical EngineeringDepartment of Electrical EngineeringCalifornia Institute of Technology1200 E.California Blvd.MC 138-78PasadenaCA 91125USA Present address:School of Precision Instruments and Optoelectronics Engineering Tianjin UniversityTianjin 300072China

Photoacoustic(PA)computed tomography(PACT)is a noninvasive hybrid imaging technique that combines optical excitation and acoustic detection to realize high contrast,high resolution,and deep penetration in biological ***,the spatial resolution of PACT is limited by acoustic ***,we report in vivo superresolution PACT,which breaks the acoustic diffraction limit by localizing the centers of single dyed droplets that are flowing in blood *** droplets were prepared by dissolving hydrophobic absorbing dye in oil,followed by mixing with *** dyed droplets generate much higher-amplitude PA signals than blood and can flow smoothly in vessels;thus,they are excellent tracers for localization-based superresolution *** in vivo resolution enhancement was demonstrated by continuously imaging the cortical layer of a mouse brain during droplet *** droplets that were flowing in the vessels were localized,and their center positions were used to construct a superresolution image that exhibits sharper features and more finely resolved vascular *** improvement in spatial resolution by a factor of 6 has been realized in vivo by the droplet localization technique.

关键词： technique. resolution dye

PHOTOACOUSTIC GENERATION OF FOCUSED QUASI-UNIPOLAR PRESSURE PULSES

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Journal of Innovative Optical Health Sciences 2010年第4期3卷 247-253页

作者： KONSTANTIN MASLOv HAO F.ZHANG lihong v.wang Optical Imaging Laboratory Department of Biomedical Engineering Washington University in St.Louis St.LouisMissouri 63130USA Department of Electrical Engineering and Computer Science University of Wisconsin-Milwaukee Milwaukee Wisconsin 53201USA

The photoacoustic effect was employed to generate short-duration quasi-unipolar acoustic pressure pulses in both planar and spherically focused *** the focal region,the temporal profile of a pressure pulse can be approximated by the first derivative of the temporal profile near the front transducer surface,with a time-averaged value equal to *** approximation agreed with experimental results acquired from photoacoustic transducers with both rigid and free *** a free boundary,the acoustic pressure in the focal region is equal to the sum of a positive pressure that follows the spatial profile of the optical energy deposition in the medium and a negative pressure that follows the temporal profile of the laser pulse.

关键词： Photoacoustics optoacoustics ultrasound generation unipolar pulse

PRELIMINARY STUDY ON SKIN CANCER DETECTION IN SENCAR MICE USING MUELLER OPTICAL COHERENCE TOMOGRAPHY

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Journal of Innovative Optical Health Sciences 2009年第3期2卷 289-294页

作者： MILOˇS TODOROvI´C SHULIANG JIAO GEORGE STOICA lihong v.wang Department of Biomedical Engineering Texas A&M University College StationTexas 77843-3120USA Department of Ophthalmology Keck School of Medicine University of Southern CaliforniaLos AngelesCalifornia 90033USA Department of Pathobiology Texas A&M University College StationTexas 77843-5547USA

We report on the use of a fiber-based Mueller-matrix optical coherence tomography(OCT)system with continuous source-polarization modulation for in vivo imaging of early stages of skin cancer in SENCAR mice.A homemade hand-held probe with integrated optical scanning and beam delivering optics was coupled in the sample *** OCT images show the morphological changes in skin resulting from pre-cancerous papilloma formations that are consistent with histology,thus demonstrating the system’s potential for early skin cancer detection.

关键词： Coherence imaging medical and biological imaging optical coherence tomography birefringence polarization turbid media

Single-pulse ultrafast real-time simultaneous planar imaging of femtosecond laser-nanoparticle dynamics in flames

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Light(Science & Applications) 2024年第10期13卷 2312-2320页

作者： Yogeshwar Nath Mishra Peng wang Florian J.Bauer Murthy S.Gudipati lihong v.wang Caltech Optical Imaging Laboratory Andrew and Peggy Cheng Department of Medical EngineeringDepartment of Electrical EngineeringCalifornia Institute of Technology1200 East California BoulevardMail Code 138-78PasadenaCA 91125USA Science Division Jet Propulsion LaboratoryCalifornia Institute of Technology4800 Oak Grove DrivePasadenaCA 91109USA Lehrstuhl für Technische Thermodynamik(LTT)and Erlangen Graduate School in Advanced Optical Technologies(SAOT) Universität Erlangen-NürnbergErlangen 91058Germany

The creation of carbonaceous nanoparticles and their dynamics in hydrocarbon flames are still debated in environmental,combustion,and material *** this study,we introduce single-pulse femtosecond laser sheetcompressed ultrafast photography(fsLS-CUP),an ultrafast imaging technique specifically designed to shed light on and capture ultrafast dynamics stemming from interactions between femtosecond lasers and nanoparticles in flames in a ***-CUP enables the first-time real-time billion frames-per-second(Gfps)simultaneous twodimensional(2D)imaging of laser-induced fluorescence(LIF)and laser-induced heating(LIH)that are originated from polycyclic aromatic hydrocarbons(PAHs)and soot particles,***,fsLS-CUP provides the real-time spatiotemporal map of femtosecond laser-soot interaction as elastic light scattering(ELS)at an astonishing 250 *** contrast to existing single-shot ultrafast imaging approaches,which are limited to millions of frames per second only and require multiple laser pulses,our method employs only a single pulse and captures the entire dynamics of laserinduced signals at hundreds of *** a single pulse does not change the optical properties of nanoparticles for a following pulse,thus allowing reliable spatiotemporal ***,we found that particle inception and growth are derived from *** essence,as an imaging modality,fsLS-CUP offers ultrafast 2D diagnostics,contributing to the fundamental understanding of nanoparticle’s inception and broader applications across different fields,such as material science and biomedical engineering.

关键词： pulse scattering dynamics

Single-pulse real-time billion-frames-per-second planar imaging of ultrafast nanoparticle-laser dynamics and temperature in flames

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Light(Science & Applications) 2023年第3期12卷 379-390页

作者： Yogeshwar Nath Mishra Peng wang Florian J.Bauer Yide Zhang Dag Hanstorp Stefan Will lihong v.wang Caltech Optical Imaging Laboratory Andrew and Peggy Cherng Department of Medical EngineeringDepartment of Electrical EngineeringCalifornia Institute of Technology1200 East California BoulevardMail Code 138-78PasadenaCA91125USA NASA-Jet Propulsion Laboratory California Institute of Technology4800 Oak Grove DrivePasadenaCA91109USA Department of Physics University of GothenburgSE 41296GothenburgSweden Institute of Engineering Thermodynamics(LTT)and Erlangen Graduate School in Advanced Optical Technologies(SAOT) Friedrich-Alexander-Universität Erlangen-Nürnberg(FAU)91058ErlangenGermany

Unburnt hydrocarbon flames produce soot,which is the second biggest contributor to global warming and harmful to human *** state-of-the-art high-speed imaging techniques,developed to study non-repeatable turbulent flames,are limited to million-frames-per-second imaging rates,falling short in capturing the dynamics of critical ***,these techniques do not provide a complete picture of flame-laser interactions,important for understanding soot ***,thermal effects induced by multiple consecutive pulses modify the optical properties of soot nanoparticles,thus making single-pulse imaging ***,we report single-shot laser-sheet compressed ultrafast photography(LS-CUP)for billion-frames-per-second planar imaging of flame-laser *** observed laser-induced incandescence,elastic light scattering,and fluorescence of soot precursors-polycyclic aromatic hydrocarbons(PAHs)in real-time using a single nanosecond laser *** spatiotemporal maps of the PAHs emission,soot temperature,primary nanoparticle size,soot aggregate size,and the number of monomers,present strong experimental evidence in support of the theory and modeling of soot inception and growth mechanism in ***-CUP represents a generic and indispensable tool that combines a portfolio of ultrafast combustion diagnostic techniques,covering the entire lifecycle of soot nanoparticles,for probing extremely short-lived(picoseconds to nanoseconds)species in the spatiotemporal domain in non-repeatable turbulent ***,LS-CUP’s unparalleled capability of ultrafast wide-field temperature imaging in real-time is envisioned to unravel mysteries in modern physics such as hot plasma, sonoluminescence, and nuclear fusion.

关键词： dynamics pulse turbulent