How Nonlinear Optical Effects degrade Hong-Ou-Mandel Like Interference

TL;DR

This paper investigates how nonlinear optical effects, caused by atoms or quantum dots in cavities, impair two-photon interference like the Hong-Ou-Mandel effect, impacting quantum optics applications.

Contribution

It demonstrates the degradation of Hong-Ou-Mandel interference due to nonlinearities and suggests using this effect to detect such nonlinearities.

Findings

Nonlinear effects reduce two-photon interference visibility.

Interference degradation can serve as a nonlinearities detector.

Avoiding nonlinearities is crucial for quantum interference applications.

Abstract

Two-photon interference effects, such as the Hong-Ou-Mandel (HOM) effect, can be used to characterize to what extent two photons are identical. Furthermore, these interference effects underly linear optics quantum computation. We show here how nonlinear optical effects, such as those mediated by atoms or quantum dots in a cavity, degrade the interference. This implies that, on the one hand, nonlinearities are to be avoided if one wishes to utilize the interference, but on the other hand, one may be able to measure or detect nonlinearities by observing the disappearance of the interference.