Terbium Gallium Garnet(TGG) The magneto-optical crystal TGG is an optimum material for Faraday devices (Rotator and Isolator) in the range from 400nm-1100nm, excluding 470-500nm.The Faraday rotator consists of a TGG rod contained inside a special designed magnet. The rotation sense of the polarization of a light beam passing through the rotator only depends on the direction of the magnetic field and not on the direction of propagation of the light beam. The optical isolator is a Faraday rotator set between two suitably aligned polarizers which allows a light beam to pass through in one direction only. TGG has a combination of excellent properties such as large Verdet constant, low light loss, high thermal conductance and high light damage threshold which makes it a unique material for Faraday devices particularly suitable for YAG lasers and Ti: sapphire tunable lasers, ring lasers and seed injected lasers. Crystal Parameters:
Chemical Formula
|
Tb 3 Ga 5 O 12
|
Lattice Parameter
|
a=12.355Å
|
Growth Method
|
Czocralski
|
Density
|
7.13g/cm 3
|
Mohs Hardness
|
8.0
|
Melting Point
|
1725 o C
|
Refractive Index
|
1.954 at 1064nm
|
Thermal Conductivity
|
9.4x10 -6oC -1
|
Verdet Constant
|
0.12min/Oe.cm at 1064nm
|
Crystal rod parameters:
|
|
Orientation
|
[111] within 5 degrees
|
Wave front Distortion
|
< l /8 wave
|
Extinction Ratio
|
> 30dB
|
Dimensional Tolerances: |
|
Diameter
|
+0.00mm/-0.05mm
|
Length
|
+0.2mm/-0.2mm
|
Chamfer
|
0.13mm (+0.00mm,-0.08mm) at 45º +/- 5º
|
End Configuration:
|
|
Flatness
|
< l /10 wave at 633nm
|
Parallelism
|
< 1 minutes of arc
|
Perpendicularity
|
< 30'
|
Scratch-dig
|
10/5 per MIL-O13830A
|