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TGG单晶具有大的磁光常数、低的光损失、高热导性和高激光损伤阈值， 广泛应用于YAG 、掺Ti蓝宝石等多级放大、环型、种子注入激光器中。 TGG单晶是用于制作法拉第旋光器与隔离器的最佳磁光材料，适用波长400-1100nm（不包括470nm-500nm）。法拉第旋光器由TGG晶棒和一个特殊设计的磁体组成。穿过磁光材料的光束的偏振方向将在磁场作用下发生偏转，其偏转方向只与磁场方向有关，与光束传播方向无关。光隔离器由一个45度偏转的旋光器和一对适当放置的偏振器组成， 它使光束仅能沿一个方向通过，而阻断反向传播的光束。
Applications Faraday Rotators and Isolators
Advantages
- TGG has twice the Verdet constant of a terbium-doped glass.
- The thermal conductivity of crystalline TGG is an order of magnitude greater than a typical glass.
- Optical losses are lower for TGG than Tb-doped glasses.
- The combination of the above factors make TGG better suited to high average power applications. The principal limiting factor is thermally induced beam distortion. Beam distortion is less for TGG than Tb-doped glasses under the same power loading level.
Material Properties
Formula
Tb3Ga5O12
Crystal Structure
[111]
Extinction Ratio
30 dB
(over 2/3 clear aperture)
Verdet Constant (632 nm)
-134 RadT-1m-1
Verdet Constant (1064 nm)
-40 RadT-1m-1
Thermal Conductivity
7.4 W cm-1 K-1
Refractive Index
1.95
Nonlinear Index, n2
8
Figure of Merit, V/a
27
Figure of Merit, V/n2
5
Tolerances
Wavefront Distortion (per inch of rod length)
l/8
Diameter
+0.000" / -0.002"
Length
+0.010" / -0.010"
Chamfer
0.005" ± 0.003"
at 45° ± 5°
Flatness
<l 10="" at="" 633nm
Parallelism
< 1 arc minute
Perpendicularity
< 10 arc minutes
Surface Quality
10-5 Scratch-Dig
(per MIL-O-1380A)
AR Coating Reflectivity
<0.25% @1064nm
Coating Adhesion/Durability
Meets MIL-C48497A
Barrel Finish (10-6 inches)
55 ± 5