Spectral Compression of Narrowband Single Photons with a Resonant Cavity

TL;DR

This paper demonstrates a method to spectrally compress narrowband single photons generated from cold rubidium atoms using an asymmetric cavity and phase modulation, achieving a bandwidth reduction close to atomic transition levels.

Contribution

The study introduces a novel spectral compression scheme for heralded single photons that is potentially lossless and compatible with atomic transitions.

Findings

Spectral bandwidth reduced from 20.6 MHz to less than 8 MHz.

Achieved spectral compression close to atomic transition linewidths.

Experimental validation using cold Rb-87 atoms and cavity-based dispersion.

Abstract

We experimentally demonstrate a spectral compression scheme for heralded single photons with narrow spectral bandwidth around 795 nm, generated through four-wave mixing in a cloud of cold Rb-87 atoms. The scheme is based on an asymmetric cavity as a dispersion medium and a simple binary phase modulator, and can be, in principle, without any optical losses. We observe a compression from 20.6 MHz to less than 8 MHz, almost matching the corresponding atomic transition.