Changes in the statistical and quantum features of the cavity radiation of a two-photon coherent beat laser due to phase fluctuation

TL;DR

This paper investigates how phase fluctuations affect the quantum and statistical properties of cavity radiation in a two-photon coherent beat laser, revealing that nonclassical features can be preserved or restored through engineering the driving mechanism.

Contribution

It provides a detailed derivation of the master equation considering phase fluctuations and demonstrates the possibility of maintaining nonclassical features despite imperfect atomic coherence.

Findings

Quantum features are significantly modified by phase fluctuations.

Nonclassical features like squeezing and entanglement can be observed without driving.

Phase fluctuations can be mitigated by engineering the driving mechanism.

Abstract

Detailed derivation of the master equation and the corresponding time evolution of the cavity radiation of a coherent beat laser when the atoms are initially prepared in a partial coherent superposition is presented. It turns out that the quantum features and intensity of the cavity radiation are considerably modified by the phase fluctuation arising due to the practical incapability of preparing atoms in the intended coherent superposition. New terms having an opposite sign with the contribution of the driving radiation emerged in the master equation. This can be taken as an indication for a competing effect between the two in the manifestation of the nonclassical features. This, on the other hand, entails that there is a chance for regaining the quantum properties that might have lost due to faulty preparation by engineering the driving mechanism and vice versa. In light of this, quite remarkably, the cavity radiation is shown to exhibit nonclassical features including two-mode squeezing and entanglement when there is no driving and if the atoms are initially prepared in a partial maximum atomic coherence superposition, contrary to earlier predictions for the case of perfect coherence.