Compensation of birefringence in active elements with a novel Faraday mirror operating at high average power

Abstract

A decrease in the depolarization ratio by more than one order of magnitude by use of a recently proposed Faraday mirror (FM) in comparison with the traditional FM has been demonstrated experimentally. At a high average laser power, the possibility of an increase in the accuracy of compensation of depolarization in the active element by means of a lambda/4 plate with both the traditional and the novel FM is shown.

Thermo-Optical and Magneto-Optical Characteristics of Terbium Scandium Aluminum Garnet Crystals

“…These devices are among those in which thermal self-action of laser radiation is most pronounced due to relatively high absorption (∼10 −3 1/cm) in magneto-optical elements (MOEs) and the need to use relatively long MOEs (∼1-2 cm). Thermally induced birefringence arising in magneto-optical elements fully determines the efficiency of the devices at high average power of transmitted radiation [5], [6]. Thus, search for methods to reduce and compensate thermal effects in Faraday devices [7], as well as search and study of the properties of new magneto-active materials with better mechanical and thermo-optical properties are of current importance.…”

Faraday Isolators for High Average Power Lasers

“…Since a laser beam induces (being a heat source) and simultaneously reads distortions, the value of self-action may depend significantly on the transverse distribution of the intensity. The results obtained can be generalized for an arbitrary axially symmetric beam (Khazanov et al, 2002b), including a super-Gaussian beam with power P 0 and intensity…”

“…In (Khazanov et al, 2002b) it was shown that [001] is the best orientation. The absorption coefficient α 0 at 1064nm wavelength in TGG can vary by several times from sample to sample, see Table 1, where values of V and κ are also included.…”

“…Second, the radiation that is incident on the MOE in FI is linearly polarized, whereas the radiation that is incident on the Faraday mirror has already been depolarized. We shall consider only FI; a Faraday mirror for high power lasers is studied in (Khazanov, 2001;Khazanov et al, 2002b;Khazanov, 2004). In the absence of thermal effects in the MOE after the first pass (from left to right), a beam retains its horizontal polarization ( Fig.…”

Long-term stabilized two-beam combination laser amplifier with stimulated Brillouin scattering mirrors

“…These Faraday rotators can also compensate the thermally induced birefringence in the amplifiers. 25,26 The SBS-PCM used in this experiment is composed of a SBS cell and a concave mirror as depicted in Fig. 2.…”