Fast optical wavefront engineering for controlling light propagation in dynamic turbid media

Abstract

While propagating inside the strongly scattering biological tissue, photons lose their incident directions beyond one transport mean free path (TMFP, [Formula: see text]1 millimeter (mm)), which makes it challenging to achieve optical focusing or clear imaging deep inside tissue. By manipulating many degrees of the incident optical wavefront, the latest optical wavefront engineering (WFE) technology compensates the wavefront distortions caused by the scattering media and thus is toward breaking this physical limit, bringing bright perspective to many applications deep inside tissue, e.g., high resolution functional/molecular imaging, optical excitation (optogenetics) and optical tweezers. However, inside the dynamic turbid media such as the biological tissue, the wavefront distortion is a fast and continuously changing process whose decorrelation rate is on timescales from milliseconds (ms) to microseconds ([Formula: see text]s), or even faster. This requires that the WFE technology should be capable of beating this rapid process. In this review, we discuss the major challenges faced by the WFE technology due to the fast decorrelation of dynamic turbid media such as living tissue when achieving light focusing/imaging and summarize the research progress achieved to date to overcome these challenges.

Single-Pixel Multimode Fiber Spectrometer via Wavefront Shaping

“…The intensity vectors are then combined into a single M × M matrix T, which is called the calibration matrix, whose rows can be used as a measure of the system response to wavelength variations. With the implementation of advanced wavefront optimization methods, it is possible to focus light in milliseconds 29 and complete the calibration of the spectrometer in less than a few minutes for many practical spectroscopy applications.…”

Optical Tissue Clearing: Illuminating Brain Function and Dysfunction

“…and reconstruction pipeline limit the broad application of this method. The optical clearing is a promising technique since deep fluorescent microscopic imaging of cleared samples may provide three-dimensional data with high spatial resolution 1 . Due to the scattering properties of tissues, many techniques such as light-sheet, two-photon, multiphoton, confocal microscopy have limited imaging depths.…”

“…Due to the scattering properties of tissues, many techniques such as light-sheet, two-photon, multiphoton, confocal microscopy have limited imaging depths. Optical wavefront engineering is a possible method to correct light wavefront distortions caused by tissue heterogeneity to increase the imaging depth and improve cellular resolution 1 . Optical clearing of tissues proposes another idea to enhance tissue uniformity, provides practical solutions to the above problems, and has broad application prospects in visualizing cross cell and organic layers 2 .…”

Editorial: Introduction to the special issue on high-resolution optical focusing and imaging within or through thick scattering media

“…For example, some have reviewed the recent progress for deeptissue high-resolution focusing and imaging based on adaptive optics and wavefront shaping, 1 point spread function deconvolution, 2 and arti¯cial intelligence. 3 Implementations for fast wavefront shaping 4 have also been summarized towards the goal of applications in dynamic scattering media and living biological tissues. Original studies presented in this issue span from the development of technology 5 and optimization algorithm 6,7 to applications for highresolution imaging 8-10 and¯ber sensing.…”