Study On Polarized Light Pumped Alkali Vapor Laser

The emergence of optical pumping enables the quantum control of atomic states to be realized.It has important applications in many fields such as laser cooling and trapping,Bose Einstein Condensation,atomic clock,etc.Alkali atoms are the main source of quantum control for optical pumping;in the field of high-energy laser,alkali laser is a new type of gas-solid fusion high-power laser that has developed rapidly in recent years,and is the only laser system expected to achieve megawatt-class output.The traditional research distinguishes the quantum control from the high-energy laser technology.In this paper,the concept of optical pumping is introduced into the research of alkali laser.For the first time,a new concept of polarized light pumped alkali laser is proposed in the world,exploring the feasibility of improving the efficiency of alkali lasers from the physical mechanism.The main research work of this paper is as follows:(1)Study on Rubidium atom absorption under magnetic field.Considering the population distribution and relaxation between Zeeman energy levels,a model based on simplified density matrix theory is established to simulate and analyze the time evolution of different Zeeman energy levels in the ground state and the effect of magnetic field.On the basis of this,the experiments of circularly polarized light pumped rubidium atomic were carried out under both vacuum and buffer gas conditions,and the influence of magnetic field on absorption was studied,which was in good agreement with the theoretical results.(2)The traditional models of alkali laser only consider the magnetic degenerate electronic energy level.For the first time,this paper establishes a polarized light pumped alkali model,considering the magnetic energy level distribution and relaxation process.According to the specific transition paths corresponding to different pump and laser states of polarization,three modes were studied: ?^+ pump,?^+ excite;? pump,? excite and ?^+ pump,?^-excite.The study includes the population distribution,laser evolution and light-light conversion efficiency.(3)Firstly successfully realized the circularly polarized light pumped rubidium laser.On this basis,it was compared with the traditional pumping methods,and the results are qualitatively consistent with the theoretical predictions.(4)We first propose and demonstrate a novel tracing atom based absorption spectroscopy method for the real-time measurement of the temperature rise and atomic concentration.The potassium atom was used as tracing atom and we successfully measured the temperature rise process in the gain medium of rubidium laser providing a new solution for high-power alkali laser diagnostic.