Development of an ultracold bright atomic beam and its application to atom interferometer

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After constructing the main experimental equipment (lasers, vacuum chambers) in H12, we have performed laser cooling experiments in H13. We have examined the spectroscopic properties of the strontium metastable state, which is the main topic of our research. After that, we have experimentally investigated the generation of an ultracold continuous scalar atomic wave using population transfer between metastable states. The results are as follows :1. Evaluation of the generation efficiency of the 5s5p ^3P_2 metastable state by using the pumping process in the magneto-optical trap (MOT)(5s^2 ^1S_0-5s5p ^1P_1). We measured the rate to be 5xl0^9 s^<-1>.2. We have measured the lifetime of the 5s5p ^3P_2 metastable state to be 500s. We found the dominant decay channel of the state to be the population transfer induced by room-temperature blackbody radiation.3. Formation of the metastable MOT (5s5p ^3P_2-5s5d ^3D_3) and continuous generation of the 5s5p ^3P_0 atomic beam using optical pumping. This scheme has the advantage that we can completely separate the states used for cooling and that used for further experiment.4. Development of a mid-infrared (MIR) light source for generating a nK atomic wave. We obtained the MIR light by optical parametric oscillation in a PPLN crystal pumped by a stable high-power laser diode. By using the MIR transition (5s5p ^3P_2-5s4d ^3D_3), the attained temperature will be 1/25 of that attained with the visible light, since the recoil temperature, which determines the cooling limit, is inversely proportional to square of the wavelength of the cooling transition