Broadband uniform-efficiency OAM-mode detector

TL;DR

This paper presents an experimental demonstration of a broadband, uniform-efficiency OAM-mode detector capable of accurately measuring high-dimensional OAM states with high fidelity, significantly advancing quantum photonics applications.

Contribution

The authors develop and experimentally validate a novel OAM detector that works across a broad spectrum with uniform efficiency and high fidelity for arbitrary quantum states.

Findings

Detects pure and mixed OAM states with over 98% fidelity.

Operates effectively for dimensionalities up to 100.

Measurement times are only a few minutes.

Abstract

The high-dimensional basis of orbital angular momentum (OAM) has several added and unique advantages for photonics quantum technologies compared to the polarization basis, which is only two-dimensional. However, one of the major roadblocks in implementing OAM-based applications with their full potentials is the absence of an ideal OAM-mode detector. Despite the plethora of efforts in the last three decades, currently, there is no OAM detector that can detect a broad OAM-mode spectrum, has uniform detection-efficiency over all the modes, measures the true spectrum, and works for an arbitrary quantum state without the need for any prior information. In this article, we experimentally demonstrate just such an OAM detector. We report detection of pure and mixed OAM states with fidelities more than 98% and with measurement times of only a few minutes for dimensionalities up to 100. We expect our work to substantially boost the OAM-based photonics quantum technology efforts.