University of Colorado

Omer Tzang

Rafael Piestun

Kelvin Wagner

Antonio Miguel Caravaca-Aguirre

Eyal Niv

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

Wavefront shaping with a 1D spatial light modulator

Recent remarkable progress in wave-front shaping has enabled control of light propagation inside linear media to focus and image through scattering objects. In particular, light propagation in multimode fibers comprises complex intermodal interactions and rich spatiotemporal dynamics. Control of physical phenomena in multimode fibers and its applications is in its infancy, opening opportunities to take advantage of complex mode interactions. Various embodiments of the present technology provide wave-front shaping for controlling nonlinear phenomena in multimode fibers. Using a spatial light modulator at the fiber's input and a genetic algorithm optimization, some embodiments control a highly nonlinear stimulated Raman scattering cascade and its interplay with four wave mixing via a flexible implicit control on the superposition of modes that are coupled into the fiber.

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Boulder, CO, United States of America

Omer Tzang