Fig. 1. Schematic of laser frequency stabilization system

Fig. 2. Flow chart of digital feedback

Fig. 3. Flow chart of automatic frequency stabilization system

Fig. 4. (a) Saturated absorption signal when there is no 87Rb D2 line in scanning range; (b) saturated absorption signal when there is 87Rb D2 line in scanning range; (c) saturated absorption signal when there is digital feedback; (d) error signal when there is no 87Rb D2 line in scanning range; (e) error signal when there is 87Rb D2 line in scanning range; (f) error signal when there is digital feedback

Fig. 5. Signals of automatic frequency stabilization system under several shocks. (a) Saturated absorption signal; (b) error signal; (c) scanning control signal

Fig. 6. Signals in the process of relocking laser after losing lock due to a shock. (a) Saturated absorption signal; (b) error signal; (c) scanning control signal

Fig. 7. Signals in the process of relocking laser after losing lock. (a) Saturated absorption signal; (b) error signal; (c) scanning control signal

Fig. 8. (a) TOF signal of the cold atom and (b) Ramsey fringes