Research Of Polarization Control In High Power Chemical Oxygen Iodine Laser Resonator And High Reflection Phase Retardance Mirror

Polarization characteristics of laser beam, which is one of the important characteristics of high power laser, have a direct effect on output power, damage threshold of optical elements and beam quality etc.The polarization characteristics in the high power COIL resonator is analyzed by Jones calculus, and draw a conclusion that, in general the eigen-polarization state is elliptical polarization. And it should be linear polarization in S direction by analyzing the relations between the reflection, absorption loss of optical thin film at oblique incidence and the polarization state, and at this time the Brewster window made of very low-absorption material can be used. In order to control the polarization characteristics, the phase retardance mirror must be used.Additionally, in order to suppress the reverse wave in ring resonator, the phase retardance mirror must also be used to preserve the polarization characteristics of the reflected reverse wave by suppressor.The conventional film stack can't satisfy the high power COIL development requirement. In this paper, we design a new film stack by use of multi-frequency design idea, which decrease the film thickness of high refraction layers greatly, and the damage threshold of it will be improved hopefully. And at the base of this film stack, by optimizing the film thickness of several outmost layers, we design the HR film at 45 incidence for 632.8nm and 1315nm with 180?or 90 phase retardance at 1315nm.At last, the designed HR phase retardance films are produced by use of the e-beam evaporation equipment, then the phase retardance and the reflection of it are measured by Lambda 900 spectrophotometer and the type of M-2000UI ellipsometer. And the error of HR phase retardance film is analyzed...