Optical focusing in scattering media with photoacoustic wavefront shaping (PAWS)

High-speed single-shot optical focusing through dynamic scattering media with full-phase wavefront shaping

Applied Physics Letters ◽

10.1063/1.5009113 ◽

2017 ◽

Vol 111 (22) ◽

pp. 221109 ◽

Cited By ~ 4

Author(s):

Ashton S. Hemphill ◽

Yuecheng Shen ◽

Yan Liu ◽

Lihong V. Wang

Keyword(s):

High Speed ◽

Single Shot ◽

Scattering Media ◽

Wavefront Shaping ◽

Optical Focusing ◽

Dynamic Scattering

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Photoacoustically guided wavefront shaping for enhanced optical focusing in scattering media

Nature Photonics ◽

10.1038/nphoton.2014.322 ◽

2015 ◽

Vol 9 (2) ◽

pp. 126-132 ◽

Cited By ~ 147

Author(s):

Puxiang Lai ◽

Lidai Wang ◽

Jian Wei Tay ◽

Lihong V. Wang

Keyword(s):

Scattering Media ◽

Wavefront Shaping ◽

Optical Focusing

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Time-reversed optical focusing through scattering media by digital full phase and amplitude recovery using a single phase-only SLM

Journal of Innovative Optical Health Sciences ◽

10.1142/s1793545815500078 ◽

2015 ◽

Vol 08 (02) ◽

pp. 1550007 ◽

Cited By ~ 1

Author(s):

Qiang Yang ◽

Xinzhu Sang ◽

Daxiong Xu

Keyword(s):

Single Phase ◽

Scattered Light ◽

Incident Light ◽

Scattering Media ◽

Ballistic Regime ◽

Light Modulator ◽

Speckle Field ◽

Biomedical Optical Imaging ◽

Wavefront Shaping ◽

Optical Focusing

Focusing light though scattering media beyond the ballistic regime is a challenging task in biomedical optical imaging. This challenge can be overcome by wavefront shaping technique, in which a time-reversed (TR) wavefront of scattered light is generated to suppress the scattering. In previous TR optical focusing experiments, a phase-only spatial light modulator (SLM) has been typically used to control the wavefront of incident light. Unfortunately, although the phase information is reconstructed by the phase-only SLM, the amplitude information is lost, resulting in decreased peak-to-background ratio (PBR) of optical focusing in the TR wavefront reconstruction. A new method of TR optical focusing through scattering media is proposed here, which numerically reconstructs the full phase and amplitude of a simulated scattered light field by using a single phase-only SLM. Simulation results and the proposed optical setup show that the time-reversal of a fully developed speckle field can be digitally implemented with both phase and amplitude recovery, affording a way to improve the performance of light focusing through scattering media.

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Focusing light into scattering media with ultrasound-induced field perturbation

Light Science & Applications ◽

10.1038/s41377-021-00605-7 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Zhongtao Cheng ◽

Lihong V. Wang

Keyword(s):

High Speed ◽

Superior Performance ◽

Single Shot ◽

Scattering Media ◽

Zeroth Order ◽

Field Perturbation ◽

Induced Field ◽

Wavefront Shaping ◽

Flexible Mechanism ◽

Optical Focusing

AbstractFocusing light into scattering media, although challenging, is highly desirable in many realms. With 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 media. Here, we report a new ultrasound-assisted technique, ultrasound-induced field perturbation optical focusing, abbreviated as UFP. Unlike 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 focusing. We find that the zeroth-order diffracted photons, although not frequency-shifted, do have a field perturbation caused by the existence of the ultrasonic guidestar. By 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 medium. We demonstrate here that UFP optical focusing has superior performance to conventional TRUE optical focusing, which benefits from the more intense zeroth-order photons. We 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 shaping. This new method upsets conventional thinking on the utility of an ultrasonic guidestar and broadens the horizon of light control in scattering media. We hope that it provides a more efficient and flexible mechanism for implementing ultrasound-guided wavefront shaping.

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