Spectrally-resolved point-spread-function engineering using a complex medium

TL;DR

This paper demonstrates a method to engineer the point-spread-function of ultrashort light pulses after passing through complex scattering media by using the multi-spectral transmission matrix, enabling precise spatio-spectral control.

Contribution

It introduces a novel technique for spectrally-resolved PSF engineering using measured MSTM and numerical filtering, expanding control over ultrashort pulse focusing.

Findings

Successful spatial and spectral PSF engineering demonstrated

Versatile control achieved through numerical filtering of MSTM

Potential applications in multiphoton microscopy

Abstract

Propagation of an ultrashort pulse of light through strongly scattering media generates an intricate spatio-spectral speckle that can be described by means of the multi-spectral transmission matrix (MSTM). In conjunction with a spatial light modulator, the MSTM enables the manipulation of the pulse leaving the medium; in particular focusing it at any desired spatial position and/or time. Here, we demonstrate how to engineer the point-spread-function of the focused beam both spatially and spectrally, from the measured MSTM. It consists in numerically filtering the spatial content at each wavelength of the matrix prior to focusing. We experimentally report on the versatility of the technique through several examples, in particular as an alternative to simultaneous spatial and temporal focusing, with potential applications in multiphoton microscopy.