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

在H12建成主要实验设备（激光器、真空室）后，我们在H13进行了激光冷却实验。我们研究了锶亚稳态的光谱特性，这是我们研究的主要课题。在此之后，我们实验研究了利用亚稳态之间的居群转移产生超冷连续标量原子波。研究结果如下：1。磁光阱（MOT）中泵送过程对55p ^3P_2亚稳态产生效率的评价（5s^2 ^ 1s_0 - 555p ^1P_1）。我们测量的速率是5x10 ^9 s^<-1>.2。我们测得555p ^3P_2亚稳态的寿命为500s。我们发现，由室温黑体辐射引起的种群转移是该状态的主要衰减通道。亚稳MOT （555p ^ 3p_2 - 555d ^3D_3）的形成及光抽运555p ^3P_0原子束的连续产生。该方案的优点是可以完全分离用于冷却的状态和用于进一步实验的状态。用于产生nK原子波的中红外光源的研制。我们在稳定的高功率激光二极管泵浦的PPLN晶体中通过光学参量振荡获得了MIR光。通过使用MIR跃迁（555p ^3P_2-5s4d ^3D_3），获得的温度将是可见光获得的温度的1/25，因为决定冷却极限的反冲温度与冷却跃迁波长的平方成反比

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