Grating Feedback Diode Laser System And Application In Cesium Magneto-Optical Trap

Beginning with the general properties of diode lasers, a homemade external cavity diode laser(ECDL) is designed , assembled and optimized. We test the characters of this ECDL and then realize frequency stabilization of the diode laser by using two different methods. We also describe the designing and construction of vapor cell magneto-optical trap(VCMOT) in our lab and show the experimental demonstration of measuring the temperature and the number of cold cesium cloud trapped in a magneto-optical trap (MOT). The main works and results we have accomplished are as follows:1) We have designed and completed a grating external cavity feedback diode laser, we are able to tune the ECDL continuously over 1.5GHz using solely the PZT. An output power of 37mW from this ECDL operating at 852nm is obtained.2) The homemade diode laser is stabilized to D₂ line of Cesium atom by using phase-sensitive detection via lock-in, The frequency jitter is less than ± 450KHz in 50 seconds.3) The homemade diode laser is also stabilized to a confocal Fabry-Perot (CFP) cavity by a dispersion-like signal which is leading from the frequency difference between axial and paraxial beams traveling through a CFP cavity. The frequencyjitter is less than ±340KHz in 50 seconds.4) A compact optical system has been designed and constructedfor our cesium VCMOT. Red-detuned locking of cooling/trapping laser to the cycling transition of cesium cooling has been accomplished by means of a double-passed acoustic-optical frequency shifting system and the technique of saturated absorption spectroscopy. The trapping beams can be independently adjusted and three double-passed circularly polarized cooling/trapping beams intersect at the center of MOT. Cesium VCMOT is successfully realized. We have summarized the basic ideas of measuring the number and the temperature of cold atom cloud by probe absorption spectrum and detecting power of fluorescence light in the standard time-of-flight method and eventually finish the measurements experimentally..The characterized work among the above is the new frequency-stabilization system which locks the home-made diode laser to a CFP cavity through a dispersion-like signal. The key point is that this is an absolute modulation-free locking technique.