Output mode simulation for high-engergy CO2 laser with mirror deformation by means of FFT

The fast Fourier transform method is used to study the mode field distribution for high-energy CO2 laser induced by the resonator mirror tilt,centre thermal distortion at the mirror and inhomogeneous gain resulting from transverse flow of gain medium.The simulation results indicate that all the above factors influence affect the mode field distribution.However the effect can be reduced by cooling resonator mirrors,adopting new mirror substrate materials,improving the reflective rate of mirror and arranging mirror tilt.