Research On Rubidium V-type Structure Two Color Polarization Spectrum

As a micro-structure technology to study the interaction between light and matter and probing the internal structure of material, spectrum is widely applied in physics, chemistry, biology, and medicine. Since 1960, spect roscopy techniques changedfundamentally with the invention of laser.Laser is used as the light source to study the emission spectrum, absorption spectrum of atoms and molecules, and the nonlinear effects. Which promote the development of atomic and molecular physics greatly. As a Doppler-free spectrum, polarization spectroscopy not onlyhas the advantages of traditional spectroscopic techniques, but also has features of high sensitivity, high resolution. At the same time,because the large dispersion-like signal at resonance, it is often used to laser frequency locking. The paper studies the new type of two-color polarization spectroscopy which put forward several years ago, takes the V level structure consists of D1 and D2 line transition of rubidium atom as example for research.On the basis of setting forth the principles of polarization spectroscopy, features, applications, research progress and analysis of present situation, theoretical and experimental studies are done for V-type structure of rubidium atomic polarization color spectrum(two-color polarization spectroscopy, TCPS). The research includes three aspects: theoretical modeling, simulation and experimental study.Firstly, establishing the rubidium V-type two-color polarization spectrum theory based on the rate equation model; calculating the normalized line strengths of D1 and D2 line transition, solving rate equations of D2 line and obtain the number of particles distribution on each magnetic sublevels. According to the formula of susceptibility calculating the polarization plane rotation angle θ of linear polarized probe light, which is proportional to the intensity of polarization spectrum. And consequently obtain the polarization spectrum.Then based on the established model, programming, calculating and simulating though matlab, get the polarization spectrum versus the variation of the probe light detuning when the pump light and the probe light propagate in different directions(same or opposite) into the medium pool. At the same time, explore the effects of media pool temperature, diameter, length pool pump light intensity and other variables on polarization spectrum.Finally, study the rubidium atomic two-color V-type polarization spectroscopy experimentally, designed the experimental setup corresponding to the theoretical model, built the experimental platform, adjusting the laboratory equipments. Get the two-color polarization spectrum through pump light and the probe light with wavelength of 780 nm and 795 nm, propagating opposite into the ru bidium vapor cell. Theoretical simulation results are compared, analyzed and summarized with the conclusion.