Coherent population trapping atomic frequency standard and method for improving short-term stability thereof

Abstract

The invention discloses a coherent population trapping atomic frequency standard and a method for improving the short-term stability thereof and belongs to the field of atomic frequency standards. The atomic frequency standard comprises a voltage controlled crystal, a polarized excitation unit, a physical unit, a servo loop, a control unit and a system relaxation time detection unit. The polarized excitation unit is used for producing microwave searching signals according to the output frequency of the atomic frequency standards; the physical unit is used for producing optical detecting signals under the effect of the microwave searching signals; the servo loop is used for producing synchronous phase demodulation signals performing synchronous phase demodulation on the optical detecting signals; the control unit is used for producing rectifying voltage affecting the voltage controlled crystal according to the synchronous phase demodulation signals; the system relaxation time detection unit is used for detecting the system relaxation time delta t of the atomic frequency standard; the control unit is further used for performing timing control on an optical switch and the servo loop of the physical unit according to the system relaxation time delta t and controlling the servo loop to perform synchronous phase demodulation on the optical detecting signals produced by the physical signals after controlling the optical switch of the physical unit to switch on for N delta t.

Description

technical field [0001] The invention relates to the field of atomic frequency standards, in particular to a coherent population trapping atomic frequency standard and a method for improving its short-term stability. Background technique [0002] Coherent Population Trapping (English: Coherent Population Trapping, referred to as: CPT) atomic frequency standard is a new type of atomic frequency standard realized by using a quantum interference phenomenon generated by the interaction between atoms and coherent lasers. The miniaturized atomic frequency standard has smaller volume and power consumption than the hydrogen atomic frequency standard and cesium atomic frequency standard, and is even much smaller than the current rubidium atomic frequency standard with the smallest volume and power consumption. [0003] The principle of the CPT atomic frequency standard is to use microwaves to modulate the laser to obtain the interaction between the two-color coherent laser and the ato...

AI Technical Summary

Problems solved by technology

[0005] When the two-color coherent laser interacts with atoms, a large number of atoms accumulate in the ground state hyperfine sub-level state, forming a polarized dark state phenomenon and cannot participate in the preparation of the CPT atomic state, thereby affecting the system signal-to-noise ratio of the CPT atomic frequency standard, which is not conducive to CPT Short-term Stability of Atomic Frequency Standard System

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