Using an acousto-optic modulator as a fast spatial light modulator

TL;DR

This paper introduces a novel high-speed, high-damage-threshold spatial light modulator using an acousto-optic modulator, enabling rapid and precise control of laser beam profiles for imaging applications.

Contribution

The authors demonstrate that an acousto-optic modulator can function as a fast, high-fidelity spatial light modulator with over 1 MHz update rate, surpassing traditional SLM limitations.

Findings

Achieved over 1 MHz pattern refresh rate.

Reconstructed 32x32 pixel images at 11.6 kHz with 98% fidelity.

Enhanced SLM performance through RF waveform optimization.

Abstract

High-speed spatial light modulators (SLM) are crucial components for free-space communication and structured illumination imaging. Current approaches for dynamical spatial mode generation, such as liquid crystal SLMs or digital micromirror devices, are limited to a maximum pattern refresh rate of 10 kHz and have a low damage threshold. We demonstrate that arbitrary spatial profiles in a laser pulse can be generated by mapping the temporal radio-frequency (RF) waveform sent to an acousto-optic modulator (AOM) onto the optical field. We find that the fidelity of the SLM performance can be improved through numerical optimization of the RF waveform to overcome the nonlinear effect of AOM. An AOM can thus be used as a 1-dimensional SLM, a technique we call acousto-optic spatial light modulator (AO-SLM), which has 50 um pixel pitch, over 1 MHz update rate, and high damage threshold. We simulate the application of AO-SLM to single-pixel imaging, which can reconstruct a 32x32 pixel complex object at a rate of 11.6 kHz with 98% fidelity.