Polarization control of a high power laser by adjoint feedback control

A technique for polarizing a high-power laser with unstable resonator optics that places the polarizing elements in a low power feedback path external to the parent resonator structure is described. The technique has been used to polarize a high-power industrial CO/sub 2/ laser. Rejection ratios for the unwanted polarizations can exceed 20 dB. The polarization vector can be rotated at will by rotating the polarizer in the low power beam path.<
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