Efficient photon sorter in a high-dimensional Hilbert space

TL;DR

This paper proposes an efficient, practical photon sorter for high-dimensional quantum states using multiplexed holograms, which could enhance quantum key distribution and quantum information processing.

Contribution

It introduces a novel holographic photon sorter based on multiplexed thick holograms, validated through coupled-mode theory for high-dimensional quantum states.

Findings

Simulated the holographic sorter with parameters matching PTR glass.

Demonstrated effective sorting in a three-dimensional state space.

Showed potential for improved quantum key distribution fidelity.

Abstract

An increase in the dimension of state space for quantum key distribution (QKD) can decrease its fidelity requirements while also increasing its bandwidth. A significant obstacle for QKD with qudits (d>2) has been an efficient and practical quantum state sorter for photons whose complex fields are modulated in both amplitude and phase. We propose such a sorter based on a multiplexed thick hologram, constructed e.g. from photo-thermal refractive (PTR) glass. We validate this approach using coupled-mode theory with parameters consistent with PTR glass to simulate a holographic sorter. The model assumes a three-dimensional state space spanned by three tilted planewaves. The utility of such a sorter for broader quantum information processing applications can be substantial.