Optimal Squeezing in the Resonance Fluorescence of Single Photon Emitters

TL;DR

This paper investigates how to optimize quantum squeezing in single photon emitters by using cavities to purify the electronic state, demonstrating robustness against environmental decoherence through analytical and numerical methods.

Contribution

It introduces a cavity-based method to achieve high purity and maximal squeezing in single photon emitters, with analytical approximations and environmental effect analysis.

Findings

Purity of electronic state exceeds 99% with realistic cavities

Squeezing remains robust under decoherence and environmental disturbances

Analytical results align well with numerical simulations

Abstract

Annual Review of Astronomy and Astrophysics, Volume 51, page 511e studied for coherently driven single photon sources, such as atoms and quantum dots. Maximal squeezing is realized, if the electronic subsystem of the emitter is in a pure quantum state. The purification is achieved by using a cavity as a second decay channel, besides the incoherent coupling to the electromagnetic vacuum. For realistic cavities this yields a purity of the electronic state of more than 99%. Aside from numerical calculations, we also derive approximate analytical results. Based on the approximations, effects are studied which originate from the environment of the emitter, including radiationless dephasing and incoherent pumping of the emitter and the cavity mode. The fragility of squeezing against decoherence is substantially reduced, so that squeezing persists even under hostile conditions. The measurement of squeezing from such light sources is also considered.