Non-contact optical wavefront shaping for focusing light and high-resolution imaging inside and behind biological scattering medium

Abstract

Optical wavefront shaping is one of the most effective techniques in focusing light inside a scattering medium. Unfortunately, most of these techniques require direct access to the scattering medium or need to know the scattering properties of the medium beforehand. Through our scheme we develop a novel concept in which both the illumination and the detection is on the same side of the inspected object and the imaging process is a real time fast converging operation that does not require to capture large plurality of images. We model the scattering medium being a biological tissue as a Matrix having mathematical properties matched to the physical and biological aspects of the sample. In our adaptive optics scheme, we aim to estimate the scattering function and thus to encode the intensity of the illuminating laser light source using DMD (Digital Micromirror Device) with an inverse scattering function of the scattering medium, such that after passing its scattering function a focused beam is obtained. We optimize the pattern to be displayed on the DMD using Particle Swarm Algorithm (PSO). As first proof of concept we show validation via numerical MATLAB simulations where we obtain a focused spot behind a scattering medium in amplitude modulation scheme.