Study On Parameters Of Alkali Metal Vapor Laser Pumped By Narrow Linewidth Lasers

In this study,the principle of narrow line width alkali metal laser is used to design a new experimental scheme and to study the light out experiments of alkali metal element potassium?K?,rubidium?Rb?,cesium?Cs?,and other elements.At the same time,the changes in the parameters of the main parameters of the alkali metal laser,such as temperature,fluorescence intensity,cavity length,lens focusing degree and focusing position,are studied.In addition,the change of the pressure of the vapor chamber will affect the efficiency of the alkali metal laser,and the pressure measurement of the vapor chamber with different pressure is measured,and the change of the pressure is observed.At the same time,helium leakage was observed in the vapor chamber filled with helium.The experimental results show that the maximum power of the vapor chamber filled with cesium and 100 Torr ethane and 300 Torr ethane respectively is 6.68mW and 31.6mW,and the slope efficiency is 2.7%and 9.4%,respectively.It is found that the effect of different pressure on slope efficiency is obvious.The higher the pressure is,the higher the slope efficiency will be.The maximum power of 14.36mW and the slope efficiency of 3.8%were achieved in the vapor chamber experiment with pure rubidium and 300 Torr ethane.For the vapor chamber filled with rubidium and cesium mixture and filled with 300 Torr ethane,the highest power obtained by cesium laser is 19.7mW,and the slope efficiency is 5.46%.The maximum output power of Rb laser is 51.61mW,and the slope efficiency is 13.7%.It is known that when mixing,the power of rubidium laser increases by 5.34mW,and the slope efficiency increases by 1.66%.For cesium element,the slope efficiency is also increased,with an increase of 4.3%.It is concluded that the luminous efficiency of rubidium and cesium is higher than that of pure rubidium or cesium.In the study of experimental parameters,it is found that the cesium laser power is the highest when the pressure is 100 Torr and the pure cesium temperature of ethane is 130?.The best value of cesium laser power for pure cesium filled with 300 Torr ethane is,when the temperature is 140?.It is known that the optimum temperature of high pressure is 10?higher than that of low pressure.The best temperature of steam pool is 300 Torr ethane,and the best power is 115?.For the rubidium cesium mixture?Rb:Cs=1:2?steam pool with a pressure of 300 Torr,the optimum temperature is 120 and 145?.Compared with the pure rubidium and cesium vapor chamber,the rubidium caesium laser is 5?larger than the pure one.For better comparison,two pump sources are used to pump rubidium cesium laser at the same time.Results the maximum power of the two lasers after mixed is 145?.This is the same as the result of a single pump.Due to the power influence of the combined power,the best temperature value of rubidium laser is pushed to a higher temperature of about 5?.When focusing lenses f=100mm,f=150mm and f=200mm,the best focusing positions are10mm,20mm and 40mm at the front of the vapor chamber,respectively.The length of the resonator is found to be maximum when the length is 200mm.In the study of D₁ and D₂ lines,it is found that for the pure cesium vapor chamber with different pressure,the absorption of high pressure is much stronger than that under the low pressure,and the same phenomenon is found in the potassium vapor chamber with different pressure.The absorption capacity of the different buffer gases in the potassium pool is found to reach the highest absorption rate at 125?,and the absorption does not increase again.The absorption rate of rubidium is faster and higher than that of potassium in the mixture of potassium and Rb.When temperature reaches 120?,it is completely absorbed.But when potassium temperature reaches 130?,the highest absorption rate is achieved.In the mixture of rubidium and cesium mixtures,the maximum absorption value of the vapor pool temperature of 1:2 is reached at 100?,but the maximum absorption value can be reached when the mixture of rubidium and cesium is 110?centigrade than the vapor pool of 2:1.Besides,their absorptivity at 90?is quite different.This may lead to different amounts of rubidium atoms in the chamber.Using the atomic absorption and spectral line widening procedure,the gas pressure in a Rb-N₂?He?vapor chamber was measured.The gas permeation in the chamber was also evaluated.In the experiment,we found that no obvious permeation can be observed in the N₂gas.For the Rb-He vapor chamber with the high pressure of 950 Torr for 60 days,the permeation of gas is measured as 19%and the leakage is deduced to be obvious.The cross sections of 5P_3/2–5P_1/2 fine structure collision transfer are measured for the vapor chamber with the Rb-N₂ pressure of 223-638 Torr.The results reveal that the collisional transfer section increases with the temperature.When the Rb-N₂ pressure is 638 Torr,the collision transfer cross sections are?1.03±0.32?×10^-16,?1.36±0.38?×10^-15,and?8.96±1.02?×10^-15cm² with the temperature of 50?,60?,and 70?,respectively.It has been demonstrated that the collision transfer section rapidly increases with the temperature when the temperature is higher than 70?.