One-atom lasers

TLDR

One‑atom lasers are important because their governing equations can be solved exactly, even with a quantized field. The study presents a fully quantum‑mechanical treatment of one‑atom lasers modeled by quantum‑optical master equations. The authors solve these master equations numerically without significant approximations, using the one‑atom laser model to investigate generic laser phenomena. They demonstrate that laser action is possible with a single atom, dominated by stimulated emission, and that under certain conditions the laser produces intensity‑squeezed light, a linewidth that increases with pumping rate, and self‑quenching when incoherent pumping is too fast.

Abstract

One-atom lasers are important because their governing equations can be solved exactly, even with a quantized field. We present a fully quantum-mechanical treatment of one-atom lasers modeled by quantum-optical master equations. These are solved numerically without any significant approximations. We show that laser action is possible with one atom, and that it might be achievable experimentally. Laser action is characterized by the dominance of stimulated emission over spontaneous emission. We use the one-atom laser model to investigate, without approximation, some interesting generic laser phenomena. Under certain conditions lasers produce intensity squeezed light, and then the laser linewidth increases with the pumping rate, in contrast with standard lasers. We also report ``self-quenching'' behavior: lasers with incoherent pumping out of the lower laser level turn off when the pumping is sufficiently fast because the coherence between the laser levels is destroyed.