Prospect for development of a pulsed CPT Raman Ramsey clock using atomic vapor

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.