Theoretical And Experimental Investigation Of Coherent Population Trapping Atomic Clock

As the most accurate tools to keep time, in the past few decades, atomic frequency standard has been considerable development. At the same time, with the development of technology and progress, The traditional atomic clock because of its large volume to be miniaturized, greatly limits the expansion of the applications of atomic clocks; with a variety of electronic devices and systems even small development of miniaturization, conventional atomic clocks, for example, satellite navigation and positioning, positioning time requiring low power consumption, small size device applications has also been a huge challenge. As a quantum interference effect, Coherent Population Trapping in atomic frequency standard has aroused widespread concern. CPT atomic clock has the advantages of small volume, low power consumption, simple structure and other advantages, and has wide application prospect in satellite navigation and positioning, information communication, time synchronization and other related fields. At present, some foreign research institutions and enterprises have been produced and can be used in satellite navigation with a small load and miniaturization of CPT atomic clock receiver products, while based on the improvement goals CPT atomic frequency stability of the development of a CPT resonance signal some improvement The new program quality.CPT effect can be achieved based on two new types of atomic clocks: CPT maser atomic clock and passive CPT atomic clock. The CPT maser atomic clock as a new type of active atomic clock, with good performance of satellite, has been designated as satellite atomic clock used in the Galileo system. Passive CPT atomic clock because there is no limit in the microwave cavity, can be designated as chip-scale atomic clocks used in miniaturization satellite navigation receiver, etc. In this thesis, the development work on the basis of NTSC CPT rubidium atomic clock, and for the development of key technologies and passive CPT atomic clock to carry out in-depth theoretical and experimental research. From the theoretical analysis of the influence of laser parameters and other factors of CPT atomic clock stability; Based on the study of the optimization of the system design, the experimental device of CPT maser atomic clock is established; For passive CPT atomic clock, the clock research to improve the CPT resonance signal of the new program, in order to further achieve passive CPT atomic clock experiment system has laid a good foundation.(1) The establishment a theory model of CPT atomic clock, using this model to study the influence of the atomic clock stability on different experimental parameters.Semi-classical theory of density matrix equations to deal with the interaction of two-color three-level atomic coherent ensemble. Solving equation under steady-state conditions, the CPT obtained based on two phenomena: Dark line with coherent microwave radiation, and then the phenomena associated with the atomic clock parameters, in order to establish a complete theoretical model was CPT atomic clock;Through the above model, through numerical analysis discussed the effects of different parameters on the rubidium atomic clock signal CPT, while in experiments on the effects of these parameters are analyzed;(2) Theoretical and experimental study of key technologies and devices of CPT maser atomic clock, the establishment and optimization of the experimental apparatus CPT maser atomic clock, get a good short-term stability.Mainly studied by EOM phase modulated laser light to produce coherent color scheme, the pilot program for the atomic clock signal and the microwave signal resonance experiments acquisition provides equal amplitude coherent light color, the scheme is applied to CPT maser atomic clock experiments; Theoretical study the role of the buffer gas in the rubidium atomic clock, given the rubidium atomic ratio of gas bubble buffer solutions; at the same time, research shows the physical system in a microwave cavity, the various parts of Rb vapor bubble, thermostatic heating element and a magnetic field and electromagnetic shielding detailed design, and finally form a complete optical and physical system design and test equipment.(3) For passive atomic clocks, atomic research to improve the CPT resonance signals of new programs, and access to high contrast compared with conventional solutions resonance signal, and lay a solid foundation for the study of passive CPT atomic clock.Experimental and theoretical studies of the Faraday effect and based on 87 Rb atomic transition line D1 high contrast CPT resonance signal acquisition program, atomic physics system in a uniform magnetic field and placed between two mutually orthogonal polarizers, polarized parallel lines coherent light through the physical system and interaction with atoms get CPT resonance signals, due to the Faraday rotation effect, a DC signal is filtered out background noise. Experiments contrast to 18% of CPT signal, the results show that the scheme through a polarization detection method effectively eliminates the CPT signal DC background, help to improve the frequency stability of miniaturization CPT atomic clocks.