Fast Generation and Detection of Spatial Modes of Light using an Acousto-Optic Modulator

TL;DR

This paper demonstrates a rapid method for generating and detecting spatial modes of light using an acousto-optic modulator, enabling high-speed quantum state tomography with high fidelity.

Contribution

The authors introduce a fast, multiplexed approach using an AOM to generate and measure spatial light modes, significantly accelerating the process compared to traditional methods.

Findings

Achieved switching rates up to 500 kHz for orbital angular momentum states.

Performed quantum state tomography in under 1 ms with 96.9% average fidelity.

Demonstrated rapid, high-fidelity measurement of spatial modes of light.

Abstract

Spatial modes of light provide a high-dimensional space that can be used to encode both classical and quantum information. Current approaches for dynamically generating and measuring these modes are slow, due to the need to reconfigure a high-resolution phase mask such as a spatial light modulator or digital micromirror device. The process of updating the spatial mode of light can be greatly accelerated by multiplexing a set of static phase masks with a fast, image-preserving optical switch, such as an acousto-optic modulator (AOM). We experimentally realize this approach, using a double-pass AOM to generate one of five orbital angular momentum states with a switching rate of up to 500 kHz. We then apply this system to perform fast quantum state tomography of spatial modes of light in a 2-dimensional Hilbert space, by projecting the unknown state onto six spatial modes comprising three mutually unbiased bases. We are able to reconstruct arbitrary states in under 1 ms with an average fidelity of 96.9%.