Ramsey spectroscopy of high-contrast CPT resonances with push-pull optical pumping in Cs vapor

TL;DR

This paper demonstrates high-contrast, narrow CPT Ramsey fringes in Cs vapor using a simple laser system with push-pull optical pumping and pulsed interrogation, advancing compact atomic clock technology.

Contribution

It introduces a novel optical setup combining push-pull optical pumping with a single Mach-Zehnder EOM for efficient CPT Ramsey spectroscopy in Cs vapor.

Findings

Achieved 166 Hz linewidth CPT Ramsey fringes

Observed 33% contrast in fringes

Used a compact, single-modulator optical system

Abstract

We report the detection of high-contrast and narrow Coherent Population Trapping (CPT) Ramsey fringes in a Cs vapor cell using a simple-architecture laser system. The latter allows the combination of push-pull optical pumping (PPOP) and a temporal Ramsey-like pulsed interrogation. An originality of the optics package is the use of a single Mach-Zehnder electro-optic modulator (MZ EOM) both for optical sidebands generation and light switch for pulsed interaction. Typical Ramsey fringes with a linewidth of 166 Hz and a contrast of 33 % are detected in a cm-scale buffer-gas filled Cs vapor cell. This technique could be interesting for the development of high-performance and low power consumption compact vapor cell clocks based on CPT.