Experimental Study Of Cesium Magneto-Optical Trap And Optical Pumping Spectrum

According to the basic principles of the semiconductor lasers, we have successfully designed and produced a grating external cavity semiconductor laser; we have established the magneto-optical trap system and realized the cesium atom's cooling and trapping. In addition, we also studied the optical pumping spectrum of Cesium D2 transition line using the home-made laser. We studied the physical mechanisms and applications of the optical pumping spectrum. The thesis mainly includes several parts:First, On the basis of commercial grating external cavity diode laser's structure and our requirements, we have designed and assembled a grating external cavity diode laser which achieved a stable single mode output. The laser works well in the vicinity of Cesium D2 line with the output wavelength stability in 852.3nm and continuous tuning range of about 3GHz.Second, we established experimental apparatus for laser cooling and trapping. We designed and established a vacuum system. The Cesium dispensers are connected to the collection cell. Typically, the collection cell pressure is about 1×10-7 Pa. We have developed a semiconductor laser system using two external cavity diode lasers(ECDLs) which are locked to certain atomic transition signal by use of saturated absorption spectroscopy. The home-made diode laser used as repumping laser. We successfully achieved 133Cs MOT.Third, we experimentally studied the optical pumping spectrum related to the cesium D2 transition line. Two perpendicular linearly polarized laser beams go through the Cs vapor cell in the same direction,the frequency of probe beam is constant but its transmission intensity will enhance or diminish with the change of the frequency of the pumping beam so as to form the optical pumping spectrum. By analyzing the optical pumping process between the ground state of cesium atoms 62S1/2 to excited state 62P3/2,we studied the physical mechanisms of the optical pumping spectrum. Without the influence of Doppler background,the line broadening will be very obvious due to the change of intensity of the probe or the pumping beam,we observed the intensity broadening under low power.The new ideas of our work can be discussed as follows:In the study of the pump-probe spectroscopy, most researchers scan the frequency of the probe laser. On the contrary, we scan the pumping laser. In addition, we have tried to eliminate the impact of Doppler background.