Limiting the incident NA for efficient wavefront shaping through thin anisotropic scattering media

Abstract

Wavefront shaping holds great potential for high-resolution imaging or light delivery either through or deep inside living tissue. However, one of the biggest barriers that must be overcome to unleash the full potential of wavefront shaping for practical biomedical applications is the fact that wavefront shaping, especially based on iterative feedback, requires lengthy measurements to obtain useful correction of the output wavefront. As biological tissues are inherently dynamic, the short decorrelation time sets a limit on the achievable wavefront shaping enhancement. Here we show that for wavefront shaping in thin anisotropic scattering media such as biological tissues, we can optimize the wavefront shaping quality by simply limiting the numerical aperture (NA) of the incident wavefront. Using the same number of controlled modes, and therefore the same wavefront measurement time, we demonstrate that the wavefront shaped focus peak to background ratio can be increased by a factor of 2.1 while the energy delivery throughput can be increased by a factor of 8.9 through 710 µm thick brain tissue by just limiting the incident NA.

Deep tissue scattering compensation with three-photon F-SHARP

“…Custom coat-ings for optical components could improve the overall transmission. Additionally, both power transmission and the number of corrected modes could potentially be improved by limiting the incident NA of the microscopy system, as suggested by Jin et al (45). In summary, 3P F-SHARP is a scattering compensation method with fast convergence on samples with arbitrary fluorescence structure.…”

Nonlinear field-control of terahertz waves in random media for spatiotemporal focusing

“…The THz field can be densely sampled in space, with patterns reaching sub-wavelength spatial resolution in the near-field region. This is a drastic difference from typical optical embodiments, where the spatial sampling is limited by the numerical aperture of the illumination 56 . On the contrary, in our case, the sampling can exceed the density of the modes accessible from the scatterer input facet, and the spatial density of the transfer matrix can be as high as required to represent the scattering medium accurately 48 .…”

Wavefront shaping: A versatile tool to conquer multiple scattering in multidisciplinary fields

“… 193 , 194 Development of faster schemes and efforts to increase the effective FOV are actively ongoing. 128 , 129 , 195 , 196 , 197 …”

“…193,194 Development of faster schemes and efforts to increase the effective FOV are actively ongoing. 128,129,[195][196][197] Thus far, WFS is the most likely solution, albeit not yet perfect, for noninvasive or minimally optical-resolution applications at depths in tissue, where conventional approaches encounter limitations owing to the lack of sufficient ballistic or quasi-ballistic photons. Under such extreme conditions, accurate wavefront measurement and control is desirable yet highly challenging.…”