Higher-dimensional Hong-Ou-Mandel effect and state redistribution with linear-optical multiports

TL;DR

This paper generalizes the Hong-Ou-Mandel effect to higher-dimensional spatial modes, enabling controllable quantum state redistribution and delayed effects using linear optical multiports without post-selection.

Contribution

It introduces a higher-dimensional HOM effect and a method for controllable quantum state redistribution with linear multiports, expanding the capabilities of quantum photonic networks.

Findings

Demonstrated higher-dimensional HOM effect in spatial modes

Achieved controllable quantum state redistribution without post-selection

Enabled spatial and temporal control of two-photon states

Abstract

We expand the two-photon Hong-Ou-Mandel (HOM) effect onto a higher-dimensional set of spatial modes and introduce an effect that allows controllable redistribution of quantum states over these modes using directionally unbiased linear-optical four-ports without post-selection. The original HOM effect only allows photon pairs to exit in two directions in space. But when accompanied by beam splitters and phase shifters, the result is a directionally controllable two-photon HOM effect in four spatial modes, with direction controlled by changing the phases in the system. This controllable quantum amplitude manipulation also allows demonstration of a "delayed" HOM effect by exploiting phase shifters in a system of two connected multiport devices. By this means, both spatial and temporal control of the propagation of the two-photon superposition state through a network can be achieved.