Terbium gallium garnet ceramic Faraday rotator for high-power laser application

Abstract

A terbium gallium garnet (TGG) ceramic Faraday rotator (FR) with an isolation ratio of 33 dB was demonstrated at a laser radiation power of 257 W. This FR can be equipped with a large optical aperture by using ceramics technology to prevent laser damage at high-energy pulse operation. The thermal lens of a 257 W laser with a beam diameter of 2.6 mm had a focal length of 9.5 m, which is easily corrected using a spherical lens to suppress the undesirable effects of thermal lensing. The rotation angle of the FR was stabilized by water cooling. The results indicate that the TGG-ceramic-based FR is suitable for high-energy laser systems with high repetition rates.

Fabrication and characterization of TGG crystals containing paramagnetic rare-earth ions

“…High-purity Tb 4 and sintered for 12 h at 1200-1400°C. Such formed materials were crushed, re-mixed and sintered again at 1200-1400°C or 24 h. Finally, we obtained polycrystalline materials.…”

“…Magneto-optical materials used in FIs are mainly crystals or ceramics with high Verdet constants (V), high thermal strength for high average power, low absorption coefficient, high damage threshold and size scalability [3,4]. For long distance communications, yttrium iron garnet (YIG) with high transparency in the infrared region is employed and it is characterized by a very large rotation angle of the polarization plane (about 220°/cm at 1300 nm [5,6]).…”

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

“…1. These ceramic samples were studied in several recent works: TGG [6][7][8][9], TAG [10][11][12]. The techniques for measuring thermally induced depolarization and thermal lens were the same in all the studies.…”

“…For TGG, the length coincided with the required one. The plots for the optical power of thermal lens as a function of the laser power obtained in [7,10,12] and recalculated for the length L = L 45 and the beam with a diameter of 2.4 mm are presented in Fig. 4.…”

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

“…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]. So far, scattering is the only drawback that impedes the practical application of TAG, so it is urgent to improve its optical qualities [12].…”