Chapter 36 Novel Scheme for Chip-Scale CPT Atomic Clock

摘要

In the presently prevailing CPT atomic clock the CPT state is prepared with either a pure left (or right) circularly polarized light, which pumps certain atoms into spin-polarized dark states thus degrading the quality of the CPT signal. The contrast (the CPT signal intensity divided by the background intensity) is normally only 4 % with this scheme. The paper presents our recently developed scheme in which laser beam is twice utilized by means of polarization reflection and the so obtained coaxial left and right circularly polarized lights simultaneously resonate with atoms, which eliminates spin-polarized dark state and stronger CPT resonance can be achieved with resonance interference enhancement. The contrast higher than 12 % of CPT signal has been obtained and the experimental result also reveals that the scheme especially suits for achieving atomic clock with good long-term behavior. Moreover, our scheme is suitable for integration, which makes it a promising candidate for both small-size and chip-scale CPT atomic clock.