Compact Rb optical frequency standard with 10 stability.

We achieved a low-cost and small-sized Rb optical frequency standard based on Rb 5S → 6P transition with 10 stability, which is comparable with that of the best 532 nm I optical frequency standards. In this system, we directly lock the 420 nm diode laser on the 5S F = 3 → 6P F = 4 hyperfine transition line without an additional Pound-Drever-Hall pre-locking system. The signal-to-noise-ratio reaches as high as 350 000 when the averaging time is at 1 s.

An all-optical locking of a semiconductor laser to the atomic resonance line with 1 MHz accuracy.

An all-optical locking technique without extra electrical feedback control system for a semiconductor laser has been used in stabilizing the laser frequency to a hyperfine crossover transition of 87Rb 5(2)S(1/2), F = 2 → 5(2)P(3/2), F' = 2, 3 with 1 MHz level accuracy. The optical feedback signal is generated from the narrow-band Faraday anomalous dispersion optical filter (FADOF) with nonlinear saturation effect. The peak transmission of the narrow-band FADOF corresponding to 5(2)S(1/2), F = 2 → 5(2)P(3/2), F' = 2, 3 crossover transition is 18.