Production And Detection Of Ultracold RbCs Polar Molecules

In ultra-cryogenics field, atomic ensemble, showing some special qualities, such as quantum fluctuation, macroscopic quantum coherence and artificial controllability, is widely used in modern science and technology, for example, the measurement of high resolution atomic spectroscopy, research and application of atomic fountain clock, the measurement of gravity acceleration by matter wave interferometer etc.On the basis of what is mentioned above, a new field, ultracold polar molecules field, gradually begins to draw researchers'attention. Ultracold polar molecules can be very wide used in many fields, for instance, the measurement of high resolution spectroscopy and fundamental physical constant, simulation of many body physics, as well as the precision measurement.More important is that according to the controllability by electric field, researchers try to use these ultracold polar molecules in quantum computation and quantum information processing, and they have started to explore for them in laboratories.In this thesis, both of ultracold cesium atom sample and rubidium atom sample are cooled and trapped at the same time in double dark-SPOT (dark spontaneous-force optical trap) magneto-optical trap. Ultracold RbCs polar molecules are produced via photoassociation. Then, the trap-loss spectrum and ion spectrum of these RbCs polar molecules are detected and researched.The main works of this paper are as follows:1. The experimental system of double dark-SPOT magneto-optical trap is established. Ultracold cesium atom sample and rubidium atom sample are cooled and trapped at the same time in this MOT. And both of them are overlapped in the center of the MOT.2. A stabilized optical system and a detection system for the production of ultracold RbCs polar molecules via photoassociation are established, which is a good experimental platform for continuing research on the ultracold RbCs polar molecules.3. Some rotational spectrum of ultracold RbCs polar molecules on the electronic bound excited state are detected by modulation and demodulation technology for ultracold atoms. These spectrum represent rovibrational energy levels of excited state (?)=0-correlated to Rb(5S1/2)Cs(6P1/2) atomic asymptote. According to these data, the photoassociation rate for ultracold RbCs polar molecules is calculated4x106s-1.4. The characteristics of microchannel plate are studied, and the optimal working parameters, which improve the detection rate and prolong the service life of the microchannel plate, are identified. RbCs+molecular ions on the triplet ground state a3∑+are detected by resonance-enhanced two photon ionization. These ion spectrum represent rovibrational energy levels of excited state (?)=0-correlated to Rb(5S1/2)Cs(6P1/2) atomic asymptote and that of excited state (2)3∏RbCs molecules correlated to Rb(5P3/2)Cs(6S1/2) atomic asymptote. In addition, the saturation effect for RbCs+molecules ions spectrum are studied, under the different impulse energy and different photoassociation laser power.