Frequency bandwidth of light focused through turbid media

TLDR

The study investigates how frequency detuning affects light focusing through turbid media. The authors shape the incident beam’s wavefront to focus light through an opaque scattering layer and validate the results with transport‑theory calculations. Detuning the laser gradually reduces focus intensity while keeping its position, size, and shape unchanged; the intensity follows the speckle correlation function, indicating that wavefront shaping can be extended to focus optical pulses in turbid media.

Abstract

We study the effect of frequency detuning on light focused through turbid media. By shaping the wavefront of the incident beam light is focused through an opaque scattering layer. When detuning the laser we observe a gradual decrease of the focus intensity, while the position, size,and shape of the focus remain the same within experimental accuracy. The frequency dependence of the focus intensity follows a measured speckle correlation function. We support our experimental findings with calculations based on transport theory. Our results imply wavefront shaping methods can be generalized to allow focusing of optical pulses in turbid media.