Controlling the propagation and interaction of light in complex media has sparked major interest in the last few years. Unfortunately, spatial light modulation devices suffer from limited speed that precludes real-time applications such as imaging in live tissue. To address this critical problem we introduce a phase-control technique to characterize complex media based on the use of fast 1D spatial light modulators and a 1D-to-2D transformation performed by the same medium being analyzed. We implement the concept using a micro-electro-mechanical grating light valve (GLV) with 1088 degrees of freedom modulated at 350 KHz, enabling unprecedented high-speed wavefront measurements. We continuously measure the transmission matrix, calculate the optimal wavefront and project a focus through various dynamic scattering samples in real-time, all within 2.4 ms per cycle. These results improve prior wavefront shaping modulation speed by more than an order of magnitude and open new opportunities for optical processing using 1D-to-2D transformations.

We present an ultra-thin hybrid imaging system based on an optical multimode fiber (MMF) and an optical fiber hydrophone that combines optical resolution photoacoustic and fluorescence microscopy. To control the illumination at the distal tip of the MMF, a digital micromirror device modulates the amplitude of the optical wavefront which is coupled into the MMF. A set of pre-calibrated speckle illuminations combined with a reconstruction algorithm enables photoacoustic and fluorescence imaging of samples located at the distal tip of the fiber with optical resolution determined by the numerical aperture.Here we employ an approach that does not require focus-1 arXiv:1812.11206v1 [physics.optics]

Speckle based imaging consists of forming a superresolved reconstruction of an unknown sample from lowresolution images obtained under random inhomogeneous illuminations (speckles). In a blind context where the illuminations are unknown, we study the intrinsic capacity of speckle-based imagers to recover spatial frequencies outside the frequency support of the data, with minimal assumptions about the sample.We demonstrate that, under physically realistic conditions, the covariance of the data has a super-resolution power corresponding to the squared magnitude of the imager point spread function. This theoretical result is important for many practical imaging systems such as acoustic and electromagnetic tomographs, fluorescence and photoacoustic microscopes, or synthetic aperture radar imaging. A numerical validation is presented in the case of fluorescence microscopy.