Quantum-jump analysis of frequency up-conversion amplification without inversion in a four-level scheme

TL;DR

This paper employs the quantum-jump approach to analyze frequency up-conversion amplification without inversion in a four-level atomic scheme, highlighting the importance of three-photon resonance for optimal gain, with implications for UV lasing.

Contribution

It provides a detailed quantum-jump analysis of AWI in a four-level system, emphasizing the role of three-photon resonance and optimizing parameters for maximum amplification.

Findings

Maximum amplification occurs at three-photon resonance.

Optimal parameters enhance probe field gain.

The study extends understanding of AWI mechanisms.

Abstract

In this work, we use the quantum-jump approach to study light-matter interactions in a four-level scheme giving rise to frequency up-conversion amplification without inversion (AWI). The results obtained apply to the case of neutral Hg vapour where, recently, it has been reported AWI of a probe field in the UV regime, opening the way for lasing without inversion in this range of frequencies. We show that, in this scheme, the key element to obtain maximum amplification is the fulfillment of the three-photon resonance condition, which favors coherent evolution periods associated with the probe field gain. We also investigate the parameter values in order to optimize amplification. The present study extends the theoretical understanding of the underlying mechanisms involved in AWI.