Optical Pumping Spectrum Of Cesium D2 Line And Its Applications

Cesium, rubidium or other alkali metal atoms with simple energy level structure often are used in experiments to study the interaction between light and atoms. Optical pumping spectrum can be obtained by detecting the absorption of the probe beam with constant frequency under the effects of the pumping beam with continuous tuning in the Cs vapor cell. It is significant to understand the atomic coherence by studying the optical pumping spectrum. We chose to analysis optical pumping spectrum of cesium D2 line and proposed approaches of offset locking between two diode lasers based on the standard of atomic hyperfine transition using this spectrum. The main works are stated as follows:The first part introduces the basic characteristics of the semiconductor laser and analysises the impact of various factors on the frequency of semiconductor laser. Then we introduce the production process of grating feedback diode laser. Finally, we introduce the frequency stabilization method using saturated absorption spectrum and its main idea is to realize the laser frequency locking based on the specific atomic transition lines as the frequency reference to obtain the frequency detection signal with a electronics negative feedback loop.The second part introduces the optical pumping spectrums. One of the two fixed-frequency lasers is used as the source of the probe beam with constant frequency and the other one is used as the source of the controlling beam with continuous tuning. With the absorption of a frequency identified and co-propagational probe beam, the optical pumping spectrums are demonstrated. The spectrums mainly reflect not only the pumping effect of the interaction berween two lights and atoms when, but also maybe quantum coherence effect between the two lights and the atom. At last, we got the optical pumping spectrums when the controlling beam and probe beam go through the Cs vapor cell in opposite or the same directions and then we analysised the meaning of the peaks in the optical pumping spectrums under different conditions.The third part focuses on the application of the optical pumping of the D2 line of cesium atoms in the realization of the techniques of offset locking between two diode lasers and analysises. And then we introduce the experimental apparatus and experimental procedure of offset locking in details and analysis the stability of offset locking between two diode lasers. We can get the optical pumping spectrums without Doppler background when the transmission of probe beam is detected with continuously tuning the pumping beam. The spectrums can provide stabe frequency signal only depends on the atomic hyperfine splittings. When achieving offset locking between two diode lasers based, we can keep interval locked between the frequency difference of the two lasers and the atomic hyperfine levels in the case that the main laser runs freely even it is continuously tuned within a certain range. At last, we introduce the use of acousto-optic modulator feedback loop to achieve frequency comb with equal space and propose the experimental idea of using light frequency comb to achieve offset locking.