Shaping speckles: spatio-temporal focussing of an ultrafast pulse through a multiply scattering medium

TL;DR

This paper demonstrates that spectral pulse shaping can achieve spatially localized temporal recompression of ultrafast pulses through a scattering medium, enabling femtosecond-scale light control with broad applications.

Contribution

It introduces a method for spatio-temporal focusing of ultrafast pulses through scattering media using spectral pulse shaping, advancing optical control techniques.

Findings

Achieved Fourier-limit temporal recompression of speckle fields

Demonstrated optical analogue of time-reversal in scattering media

Enabled femtosecond-scale light manipulation through complex media

Abstract

The multiple scattering of coherent light is a problem of both fundamental and applied importance. In optics, phase conjugation allows spatial focussing and imaging through a multiply scattering medium; however, temporal control is nonetheless elusive, and multiple scattering remains a challenge for femtosecond science. Here, we report on the spatially and temporally resolved measurement of a speckle field produced by the propagation of an ultrafast optical pulse through a thick strongly scattering medium. Using spectral pulse shaping, we demonstrate the spatially localized temporal recompression of the output speckle to the Fourier-limit duration, offering an optical analogue to time-reversal experiments in the acoustic regime. This approach shows that a multiply scattering medium can be put to profit for light manipulation at the femtosecond scale, and has a diverse range of potential applications that includes quantum control, biological imaging and photonics.