Method and device for obtaining Ramsey-CPT spectrum

Abstract

The invention discloses a method for obtaining a Ramsey-CPT spectrum. The method includes the steps that a current periodically switched between I<1> and I<2> is coupled with microwaves to be input into a laser tube, wherein when the laser tube works with the current I<1>, the power of a positive first-stage sideband and the power of a negative first-stage sideband in polychromatic light output by the laser tube are maximum, and the frequency meets the requirement for CPT resonance with alkali metal atoms; after the current is switched, the jumping probability of all frequency components of the polychromatic light output by the laser tube and the alkali metal atoms is almost zero. In this way, the alkali metal atoms are switched between the state of being acted with lasers to generate CPT resonance and the interaction-free free relaxation state, and therefore Ramsey-CPT interference is generated. The invention further discloses a device for obtaining the Ramsey-CPT spectrum. By means of the scheme, a Ramsey-CPT atomic clock which is the same as a fashionable CPT atom clock in size and power consumption and better than the fashionable CPT atom clock in frequency stability can be achieved.

Description

technical field [0001] The invention relates to the field of passive coherent population trapping (CPT, Coherent Population Trapping) atomic clocks, in particular to a method and device for obtaining Ramsey-CPT spectra by switching current amplitudes. Background technique [0002] Passive CPT atomic clock is a kind of atomic clock that can achieve chip-level size. The principle is to use coherent dichromatic light whose frequency difference is controlled by microwave frequency to interact with alkali metal atoms to achieve CPT resonance. The CPT signal determined by the hyperfine energy level difference of the atomic ground state The microwave frequency is discriminated to form a negative feedback loop to lock the microwave frequency with the atomic ground state hyperfine energy level difference, thereby realizing the stable frequency output of the atomic clock. [0003] The current popular small-scale CPT atomic clock scheme is to use a microwave-modulated current-driven...

AI Technical Summary

Problems solved by technology

This solution only adds a microwave switch to the circuit, so it is possible to realize a practical small atomic clock, but because it is difficult to achieve ideal impedance matching, it will cause microwave reflection and microwave transient radiation to generate noise during the switching process, making it difficult to implement this solution. ideal effect

More importantly, this scheme is monochromatic light interacting with atoms during the microwave disconnection period. At this time, the modulation index of the microwave to the input VCSEL current is zero. According to the relationship between the optical frequency shift and the modulation index, the optical frequency shift generated is very Large, not conducive to improving the long-term stability of atomic clocks

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