Novel Faraday mirror for lasers with high average power

Summary form only given. Because of the recent increase in the average laser power the study of the thermal effects caused by the absorption of laser radiation in Faraday isolators and Faraday rotators becomes ever more topical. Unlike isolators, the Faraday rotator is used not for optical isolation but, as a rule, for compensation of birefringence in active elements (AE) of powerful laser systems. The combination of a Faraday rotator and a mirror is called a Faraday mirror (FM). FM is effectively employed in laser amplifiers and oscillators. If the Faraday rotator introduces, owing to the thermally induced effects, the polarization distortions (depolarization), the compensation of birefringence in AE will be only partial. Two-elements designs cannot improve parameters of FM in this case. We suggest and investigate a novel FM. We compare the effectiveness of birefringence compensation of this mirror with the traditional design and the design with a /spl lambda//4.5.