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

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 of 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. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This study demonstrates the manipulation of ultrashort light pulses through strongly scattering media using a multi-spectral transmission matrix (MSTM), showing how to engineer the spatial and spectral characteristics of the focused beam's point-spread function. Experimental results showcase the versatility of the technique as an alternative to simultaneous spatial and temporal focusing, with potential applications in multiphoton microscopy.