Research On Intelligent Technology Of Laser Frequency Automatic Stabilization For Atomic Interferometer

Owing to the advantage of shorter material wavelength brought by the larger atomic mass,the resolution of the atomic interferometer is several orders of magnitude higher than that of the optical interferometer under the same conditions.So the technology of inertial measurement based on the atomic interferometer shows superior potential performance and broad application prospects.Based on the research of atomic interference gravimeter,this thesis studies the stabilization technology of laser frequency and power.The aim is to narrow the laser line width,promote its frequency stability,improve the laser power stability,and to achieve the automation of laser frequency stabilization system.The main work of the thesis is summarized as follows:1.The quality requirements of lasers in atomic interferometers are pointed out,and the technical ways to solve practical problems are clarified.The typical laser frequency stabilization method is discussed from the three components of the closed-loop frequency stabilization system,that is the reference frequency,frequency discrimination method and feedback control.In addition,the concept,function and technical solutions of the automatic laser frequency stabilization system are clarified.2.A closed-loop laser frequency stabilization system based on modulation transfer spectrum have been designed and implemented.The system consisting of a laser device,a frequency discriminator,and a feedback controller,is designed to lock the laser frequency to the ultrafine transition frequency of Rb atoms.After laser frequency locking,the laser line width is about 60 kHz,and the relative frequency stability reaches1.2×10^-12@30s.What's more,experiments show that the system can run stably for a long time under the environment of less interference.3.A intelligent recognition technology of SAS based on support vector machine is proposed to realize the automatic frequency stabilization of laser.Combining the pattern recognition technology in artificial intelligence with classical optoelectronic technology,judging the working state of the laser through the intelligent recognition technology of SAS,the system can accurately and automatically tune the laser frequency,search for lockable points in SAS.Based on the closed-loop laser frequency stabilization system,a dual-loop control structure is built to realize the complete automatic frequency stabilization process,which enables the system to have the function of one-button laser locking and automatic relocking.The average relocking time of multiple experiments is56 seconds that shows a fast response.4.An externally controlled laser power stabilization system based on AOM was developed.The laser power stability is limited to 0.06%under different conditions,and the power response time of power stabilizing is better than 90us.The system effectively suppresses laser power noise at different frequencies,reducing the low frequency drift noise to-63dB/Hz.It can effectively reduce the measurement noise introduced by laser power fluctuations and exhibits important practical value in atomic interference gravimeters.