Study On Resonator With 90° Conical Reflector For High Power Transverse Flow CO₂ Laser

The thesis has experimentally researched 90°conical reflector resonator for 5 kW continuous transverse flow CO₂ laser on the basis of analyzing common resonators. The aim is to explore new resonator with lower misalignment sensitivity and high beam quality output.The performance of several common resonators on high power transverse flow CO₂ laser is analyzed. Diffraction integral equation and its solution are also analyzed. For the V-type resonator, the laser spot radius of TEM00 is calculated by using matrix optics theory, the corresponding diffraction integral equation is derived according to Kogelnik's principle.On the basis of equivalent resonator theory, the simplified model of 90°conical reflector resonator and diffraction integral equation are given, the method with finite element numerical matrix is used for solving equations, the priority output beam mode is computed by Matlab, the tolerance of conical vertex angle is analyzed. The influence of beam quality caused by the change of gain medium along gas flow direction can be compensated by 180°reflection of beam.Output characteristics of 90°conical reflector resonator is researched on high power transverse-flow CO₂ laser, the result of numeral simulation is consistent with experimental output laser mode. It indicates that small processing blind-hole and appropriate cooling method can effectively improve beam quality.This thesis innovates to apply 90°conical reflector resonator to continuous transverse flow CO₂ laser. So it has important significance for high power transverse flow CO₂ laser.