Compensating for Beamsplitter Asymmetries in Quantum Interference Experiments

TL;DR

This paper demonstrates that polarization manipulation can fully compensate for asymmetries in beamsplitters, restoring high quantum interference visibility in Hong-Ou-Mandel experiments with asymmetric beamsplitters.

Contribution

The authors introduce a method to compensate for beamsplitter asymmetries using polarization control, enabling near-perfect quantum interference visibility.

Findings

Compensation increased dip visibility from 22% to 99%.

Method effective with highly asymmetric 10/90 beamsplitters.

Experimental validation confirms theoretical predictions.

Abstract

The visibility of the quantum interference "dip" seen in the Hong-Ou-Mandel experiment is optimized when a symmetric 50/50 beamsplitter is used in the interferometer. Here we show that the reduction in visibility caused by an asymmetric beamsplitter can be compensated by manipulating the polarization states of the two input photons. We experimentally demonstrate this by using a highly asymmetric 10/90 beamsplitter, and converting an initial dip visibility of 22% to a compensated value of 99%.