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Crystals Optical Crystals TGG

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
Standard TGG rod specification:
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
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