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

A technology of coherent population trapping and atomic frequency standard, applied in the field of atomic frequency standard, can solve the problems of the system signal-to-noise ratio that affects the CPT atomic frequency standard, and the short-term stability of the system that is unfavorable to the CPT atomic frequency standard, and achieves the advantages of short-term stability, The effect of improving the signal-to-noise ratio

CN104410416AActive Publication Date: 2015-03-11JIANGHAN UNIVERSITY
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2015-03-11

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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.
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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...

Examples

Embodiment 1

[0052] An embodiment of the present invention provides a coherent population trapped atomic frequency standard, see figure 1 , the atomic frequency standard includes:

[0053] Voltage controlled crystal oscillator 101;

[0054] The linear polarization excitation unit 102 is used to generate a microwave search signal according to the output frequency of the voltage-controlled crystal oscillator;

[0055] The physical unit 103 is used to generate a two-color coherent laser under the modulation of the microwave search signal, and the two-color coherent laser interacts with atoms to generate a photodetection signal;

[0056] The servo loop 104 is used to perform synchronous phase detection on the optical detection signal to generate a synchronous phase detection signal;

[0057]The control unit 105 is used to generate a correction voltage to act on the voltage-controlled crystal oscillator according to the synchronous phase detection signal;

[0058] A system relaxation time de...

Embodiment 2

[0084] The embodiment of the present invention also provides a method for improving the short-term stability of the coherent population trapped atomic frequency standard, see Figure 4 , the method includes:

[0085] Step 201: Detect the system relaxation time Δt of the atomic frequency standard.

[0086] Specifically, step 201 can be implemented in the following manner:

[0087] Step 1: The ring oscillator is used to receive the output signal of the servo loop, and the output signal of the servo loop is inverted and output.

[0088] Step 2: Control the switching of the optical switch in the physical unit according to the output signal of the ring oscillator.

[0089] Step 3, measuring the oscillation period of the atomic frequency standard according to the output signal of the ring oscillator.

[0090] Step 4, obtaining the oscillation period of the ring oscillator.

[0091] Step 5, calculating the system relaxation time of the atomic frequency standard according to the o...