Study of the properties and prospects of Ce:TAG and TGG magnetooptical ceramics for optical isolators for lasers with high average power

Abstract

The prospective magnetooptical TGG, TAG and Ce:TAG ceramics for large-aperture Faraday isolators for lasers with average power more than 100W are compared. TGG ceramics is 1.5 times inferior to TGG crystals, whereas TAG ceramics is comparable with TGG crystals in maximum radiation power at the same isolation ratio. Optical power of their thermal lenses is also identical. Improvement of ceramics growth technologies and using doping for increasing Verdet constant is expected to additionally reduce thermal distortions in ceramics.

Thermo-optical and magneto-optical characteristics of CeF 3 crystal

“…However, thanks to the advances in production technologies of new optical crystals and ceramics a number of optical media with better thermal and magneto-optical properties are already known, for example, TSAG [1e3] and NTF [4] crystals, as well as TAG [5] and Ce:TAG [6] ceramics.…”

Vacuum sintering of Tb3Al5O12 transparent ceramics with combined TEOS+MgO sintering aids

“…Its Verdet constant is approximately -172.72 rad/Tm at a wavelength of 632.8 nm and the thermal conductivity is approximately 6.5 W/mK at room temperature [8]. The investigation of both pure and doped TAG transparent ceramics in recent years also showed that the isolation ration, thermally induced depolarization and thermal lens were all superior to or comparable with the most commonly used Tb 3 Ga 5 O 12 (TGG) single crystals [9][10][11][12]. Furthermore, the excellent size scalability of transparent ceramics could prevent laser damage in these high energy systems [13,14,15].…”

“…Furthermore, the excellent size scalability of transparent ceramics could prevent laser damage in these high energy systems [13,14,15]. So far, scattering is the only drawback that impedes the practical application of TAG, so it is urgent to improve its optical qualities [12].…”

TSAG-based cryogenic Faraday isolator

“…Reducing the length of the MOE also allows to reduce thermally induced effects. The creation of materials with high Verdet constant now is an area experiencing active development, there are many attempts to create material combining high Verdet constant value and good magnetooptical properties: creation of TGG and TAG optical ceramics and crystals, including doping with rare earth ions of Ce and Pr [6][7][8][9][10], fluoride-based materials [11] and others [12][13][14][15].…”

“…TSAG Verdet constant is $20% higher than the Verdet constant of traditionally used as MOE terbium gallium garnet crystals (TGG) and TGG ceramics [7,22] and TSAG thermooptic constant Q is very small [23], which leads to an extremely low value of thermally induced depolarization in the crystal. Furthermore TSAG has extremely high absolute value of the optical anisotropy parameter n = À101 [23], which gives difference between the minimum and maximum levels of depolarization exceeds 4 order of magnitude.…”