Polarization-resolved microscopy through scattering media via wavefront shaping

TL;DR

This paper demonstrates that wavefront shaping can restore focus and recover polarization states in scattering media without polarizing optics, enabling deep polarization-resolved microscopy and SHG imaging of tissues.

Contribution

It introduces a novel method to achieve polarization recovery through wavefront shaping without polarizing optics, extending deep imaging capabilities.

Findings

Wavefront shaping restores focus and polarization in scattering media.

Polarization state recovery occurs without polarizing detection optics.

Successful deep tissue SHG imaging of collagen fibers was demonstrated.

Abstract

Wavefront shaping has revolutionized imaging deep in scattering media, being able to spatially and temporally refocus light through or inside the medium. However, wavefront shaping is not compatible yet with polarization-resolved microscopy given the need of polarizing optics to refocus light with a controlled polarization state. Here, we show that wavefront shaping is not only able to restore a focus, but it can also recover the injected polarization state without using any polarizing optics at the detection. This counter-intuitive effect occurs up to several transport mean free path thick samples, which exhibit a speckle with a completely scrambled state. Remarkably, an arbitrary rotation of the input polarization does not degrade the quality of the focus. This unsupervised re-polarization - out of the originally scrambled polarization state - paves the way for polarization-resolved structural microscopy at unprecedented depths. We exploit this phenomenon and demonstrate second harmonic generation (SHG) structural imaging of collagen fibers in tendon tissues behind a scattering medium.