Shi F.,Science and Technology on Metrology and Calibration Key Laboratory |
Shi F.,Beijing Institute of Radio Measurement and Metrology |
Yang R.,Science and Technology on Metrology and Calibration Key Laboratory |
Yang R.,Beijing Institute of Radio Measurement and Metrology |
And 12 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015
In this work, a portable atomic frequency standard based on coherent population trapping is designed and demonstrated. To achieve a portable prototype, in the system, a single transverse mode 795nm VCSEL modulated by a 3.4GHz RF source is used as a pump laser which generates coherent light fields. The pump beams pass through a vapor cell containing atom gas and buffer gas. This vapor cell is surrounded by a magnetic shield and placed inside a solenoid which applies a longitudinal magnetic field to lift the Zeeman energy levels"™ degeneracy and to separate the resonance signal, which has no first-order magnetic field dependence, from the field-dependent resonances. The electrical control system comprises two control loops. The first one locks the laser wavelength to the minimum of the absorption spectrum; the second one locks the modulation frequency and output standard frequency. Furthermore, we designed the micro physical package and realized the locking of a coherent population trapping atomic frequency standard portable prototype successfully. The short-term frequency stability of the whole system is measured to be 6×10-11for averaging times of 1s, and reaches 5×10-12at an averaging time of 1000s. © 2015 SPIE.