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European Frequency and Time Forum

VCSEL-based Raman frequency reference on Rubidium atoms

Laurent P. Balet, Jacques Haesler, Steve Lecomte

Published Apr 1, 2012• 1 citation
Publisher

Abstract

As an alternative to coherent population trapping (CPT), stimulated Raman scattering in an atomic vapor and implemented in an optoelectronic microwave oscillator can be designed as a compact microwave frequency reference. Due to its simplified architecture and as an active atomic clock, it has the potential to be less energy demanding than CPT. In this paper, we present experimental results on the behavior and frequency stability of a tabletop Raman oscillator.

DOI
10.1109/eftf.2012.6502391

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The phenomenon of all-optical Ramsey interference using pulsed coherent population trapping (CPT) beams provides a new avenue for developing frequency standards using atomic vapor. In this study, we show that frequency narrowed Ramsey fringes can be produced in rubidium vapor without the effect of power broadening. We observed fringes of width as narrow as 1 kHz using a buffer-gas filled rubidium cell. A compact injection-locked laser (ILL) system was used to generate CPT beams. Studies also show that ac Stark effect on Ramsey fringes can be reduced, and higher frequency stability can be achieved in a clock application. The results are encouraging to propose an architecture for development of a pulsed CPT Ramsey clock. In this paper, we also provide related discussions on clock frequency stability, and our plans for future experiments.
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