Magneto-optic rotation detection scheme for miniaturized coherent population trapping atomic clock.

In order to suppress the effects of carrier and high-order sidebands on the coherent population trapping (CPT) signal, a scheme of interaction between an elliptically polarized beam and alkali atoms using the magneto-optic rotation detection is examined. By canceling the spin-polarized dark state in the CPT state preparation, a CPT resonance signal with a contrast of 32.5% is obtained. Our scheme requires minor modifications of the optical path in the prevalent scheme, and the short-term frequency stability of our scheme is five times better than that of the prevalent scheme, making it ideal for miniaturized CPT atomic clock applications.

Interference-enhanced and power-reduced CPT atomic realization approach with an external cavity.

A scheme is studied for a coherent population trapping (CPT) atomic clock with counterpropagating left and right circularly polarized lasers, wherein the vertical-cavity surface-emitting laser and the partially reflecting mirror form an external cavity of an established length. With cancellation of spin-polarized dark states and interaction repeated with atoms, a CPT signal is obtained that is eight times larger than that of the conventional scheme. For the improvement of modulation efficiency, CPT resonance still can be excited with a lower microwave power compared with the conventional scheme. The experimental results suggest that it is an alternative for low-power atomic clocks.