Research On High-power Laser Beam Combining Dichroic Mirror

Spectral beam combining based on edge filter multiplies output power by using the cutoff characteristic.It has the advantages of high efficiency,good beam quality,high output power,simple structure and good stability.In recent years it has become a new research area in the field of high power laser beam combining.As the core component of the system,the optical characteristics of edge filter have a significant impact.Firstly,the development and application of laser beam combining system are introduced,the basic principle is summarized,and the development of scattering theory,coating and monitoring technology of edge filter are described.A reflection model of multilayer rough surface was established.TFCalc software was used to design and optimize the multilayer structure of edge filter.The reflectivity of edge filter was simulated,and the main factors affecting the reflectivity were analyzed.Furthermore,the evaluation index of system output was established,modeling and simulation of combining efficiency and beam quality of system were carried out.And the target of key parameters of high power spectral beam combining edge filter were proposed.In cooperation with the advanced factory,a high power spectral beam combining edge filter was obtained.The key parameters were measured and the simulation results were compared with the measurement results.The rationality of the theoretical model was verified and the reasons for the differences were analyzed.Finally,the edge filter was applied to the spectral beam combining system,and the output of the system was measured.This spectral beam combining system now has achieved a high-power output of more than 10.12 k W.The combining efficiency is higher than 97%,and it can reach 98.9% at the highest power output.