A Research On Dual-wavelength Laser Amplifier Based On The Intra-cavity Pumping

Dual-wavelength solid-state lasers have demonstrated widespread prospects for applications in laser detection,information transfer,and new industries.It has since emerged as a popular international research topic due to its simultaneous output of multiple significant wavelengths and its compact structure.At present,the predominant approach to obtaining dual-wavelength laser output is based on a single laser gain medium,which faces the drawback of intense gain competition between its leap spectral lines.Hence,this results in bottlenecks such as low output power and low conversion efficiency.The primary oscillation power amplification technology is ideally suited to achieve high-power,high-quality laser output.However,the current reports on laser amplifiers only amplify the output for a single wavelength.For this reason,this thesis proposes a new technical solution in which the intracavity pumping technique is integrated with the main oscillation power amplification technique where the in-tracavity pumped dual-wavelength laser is employed as the main oscillator of the laser amplifier.Since the two wavelength lasers of 0.9 μm quasi-triple energy level and 1.0 μm quadruple energy level are generated in their respective gain media,the gain competition between the leap spectral lines can be fundamentally eliminated.As such,it is able to output a no gain competition dual-wavelength seed light.Based on this,the primary oscillation power amplification technique is being introduced to achieve dual-wavelength simultaneous amplified output by placing the dual-wavelength seed lightly in the laser amplification stage to obtain a no gain competition,high-quality,high power as well as highly stable dual-wavelength laser output.The principal research carried out in this thesis and the results obtained are as follows:Based on the theory of intra-cavity pumping technology,the physical model of the seed light of intra-cavity pumped dual-wavelength laser amplifier with reabsorption effect has been successfully established,and the rate equation of intra-cavity pumped dual-wavelength with reabsorption effect has been effectively resolved.At the same time,the relationship between the output power of seed light and pump power of dual-wavelength laser amplifier with reabsorption effect has been successfully obtained.On this basis,the physical model of a dual-wavelength laser amplifier based on intra-cavity pumping technology has been constructed based on the principle of laser amplifier,and the relationship between the output power and pump power of the laser amplifier has been obtained based on the transport equation.The optimal design of the structure of the dual-wavelength laser amplifier has been conducted,the amplification stage crystal has been selected,and the thermal effects of different crystals have been comprehensively analyzed.The optimal parameter values of the crystal have been determined by simulating the thermal effect diagram of the crystal at different doping concentrations and the thermal distribution of the crystal at different pump spot sizes.The amplification stage pumping method is analyzed and the LD end-surface pumping method is defined as the amplification stage pumping method for the dualwavelength laser amplifier.A theoretical analysis of the resonant cavity of the intra-cavity pumped dual-wavelength laser is undertaken using the ABCD matrix,and the exact resonant cavity stability region of the laser resonant cavity is calculated and optimized to successfully attain the accurate cavity length parameters and the resonant cavity stability region range.Ultimately,the output characteristics of a dual-wavelength laser amplifier on the basis of the intra-cavity pumping technique have been successfully simulated.Firstly,the output characteristics of the main oscillator are investigated: the effect of different crystal lengths and absorption indices of the four-energy crystal on the number of photons in the cavity.Simultaneously,the transmission rates of the four-energy and quasi-three-energy output mirrors are optimized and the seed light output characteristics of the dual-wavelength laser amplifier based on the intra-cavity pumping technique have also been thoroughly investigated.Secondly,the output characteristics of the laser amplifier are simulated to comprehensively assess the effects of amplifier crystal length,spot size,beam overlap efficiency,mode matching,dual-wavelength seed laser power as well as amplifier extraction efficiency on the output characteristics of the dual-wavelength laser amplifier.Therefore,according to the simulation results,the optimal parameters are optimally designed to successfully achieve an efficient output of the dual-wavelength laser amplifier.