Fast control of the transverse structure of a light beam using acousto-optic modulators

TL;DR

This paper demonstrates a method to rapidly control the transverse structure of light beams in two dimensions using acousto-optic modulators, enabling high-speed, high-fidelity generation of complex optical modes for advanced applications.

Contribution

The authors extend acousto-optic modulation to 2D beam shaping with a double-AOM scheme, achieving fast, high-fidelity generation of Hermite-Gaussian modes.

Findings

Achieved 81% average fidelity in 2D Hermite-Gaussian modes.

Generated high-order mode HG_53 with 56% fidelity.

Demonstrated 20 MHz refresh rate for 1D spatial mode control.

Abstract

Fast, reprogrammable control over the transverse structure of light beams plays an essential role in applications such as structured illumination microscopy, optical trapping, and quantum information processing. Existing technologies, such as liquid crystal on silicon spatial light modulators (LCoS-SLMs) and digital micromirror devices (DMDs), suffer from limited refresh rates, low damage thresholds, and high insertion loss. Acousto-optic modulators (AOMs) can resolve the above issues, as they typically handle higher laser power and offer lower insertion loss. By effectively mapping the temporal radio-frequency (RF) waveforms onto the spatial diffraction patterns of the optical field, individual AOMs have been shown to generate one-dimensional (1D) spatial modes at a pixel refresh rate of nearly 20 MHz. We extend this concept to enable fast modulation in a two-dimensional (2D) space using a double-AOM scheme. We demonstrate the generation of 2D Hermite-Gaussian (HG_nm) modes with an average fidelity of 81%, while the highest-order mode generated, HG_53, retains a fidelity of 56%.