Flexible generation of correlated photon pairs in different frequency ranges

TL;DR

This paper demonstrates a method to generate correlated photon pairs at tunable frequencies, including the THz range, using an off-resonant laser interacting with a symmetry-broken two-level system, producing non-classical light.

Contribution

It introduces a novel approach for frequency-tunable correlated photon pair generation leveraging symmetry-breaking in two-level systems.

Findings

Photon pairs exhibit strong intensity correlations.

Laser intensity controls correlation degree.

Photon frequency can be tuned into the THz domain.

Abstract

The feasibility to generate correlated photon pairs at variable frequencies is investigated. For this purpose, we consider the interaction of an off-resonant laser field with a two-level system possessing broken inversion symmetry. We show that the system generates non-classical photon pairs exhibiting strong intensity-intensity correlations. The intensity of the applied laser tunes the degree of correlation while the detuning controls the frequency of one of the photons which can be in the THz-domain. Furthermore, we observe the violation of a Cauchy-Schwarz inequality characterizing these photons.