DDS (Direct Digital Frequency Synthesizer) frequency hopping device used for laser time sequence control of cold atom interferometer

Abstract

The invention relates to a DDS (Direct Digital Frequency Synthesizer) frequency hopping device used for the laser time sequence control of a cold atom interferometer. The device comprises an upper computer with a LABVIEW control program, an ARM (Advanced RISC Machines) chip, a CPLD (Complex Programmable Logic Device) chip, a rubydium atomic clock, a radio frequency chip and a DDS chip. The setting of frequencies required for the atomic velocity selection and the microwave frequency mixing of the cold atom interferometer as well as for an atomic wave packet to carry out beam splitting, inversion and beam combination under a function of a [Pi] / 2-[Pi]-[Pi] / 2 Raman pulse sequence can be realized. The device adopts the following methods that the rubidium atomic clock is used for replacing a common quartz crystal oscillator, and the reference crystal oscillator of the complex programmable logic device chip and the reference crystal oscillator of the DDS chip use the same radio frequency source. Compared with a traditional DDS frequency hopping device, the device disclosed by the invention is characterized in that the setting of the frequencies of different hopping frequencies and frequency time intervals can be realized, and the device exhibits a higher phase noise level and higher phase continuity on an aspect of output frequency switching.

Description

technical field [0001] The invention relates to a DDS frequency hopping device used for laser timing control of a cold atom interferometer. Background technique [0002] The cold atom interferometer utilizes the small velocity and velocity distribution and good coherence of cold atomic clusters. The free-falling cold atomic clusters are used as the test mass, and lasers are used to manipulate cold atoms to achieve matter wave interference to obtain the gravity of the falling area of ​​cold atoms. The magnitude of the acceleration. The cold atom interferometer is mainly based on the stimulated Raman transition (SRT) of two photons to change the energy state inside the atom, split, reverse and combine the beams of the atoms, and finally form interference. 87 Rb atoms are first loaded in the three-dimensional magneto-optical trap, Rb is rubidium atom, 87 is the isotope of rubidium atom, and it is cooled to 4μk before free falling. k is the thermodynamic temperature Kelvin, μk...

AI Technical Summary

Problems solved by technology

[0005] The current existing technology has the disadvantages that the signal source frequency and time interval cannot be set, the DDS signal source phase noise level and phase continuity and other indicators are not high, and the scheme adopted by the timing control is relatively complicated to use. The present invention overcomes the above-mentioned shortcomings of the prior art. Shortcomings, in view of the special requirements of the laser timing control of the cold atom interferometer, a DDS frequency hopping device for the laser timing control of the cold atom interferometer is proposed

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