TGG Crystals
Large Verdet Constant: Approximately 40 Rad T^-1 m^-1, indicating strong magneto-optical effects.
Superb Thermal Properties: Thermal conductivity of 7.4 W/m/K, providing excellent thermal management.
Low Optical Losses: Less than 0.1% per centimeter, ensuring minimal light attenuation.
High Damage Threshold: Can withstand laser-induced damage thresholds greater than 1 GW/cm².
Better Performance: Outperforms terbium-doped glasses in high average power fiber lasers due to greater Verdet constant and lower optical losses.
Applications: Faraday Rotators, Magneto-Optical Modulators, Circulators, Current Measuring Transducers, etc.
TGG crystal, with the chemical composition TbGa5O12, is a widely used magneto-optical material for manufacturing Faraday rotators and various other magneto-optical components. Its transmission range spans from visible to near-infrared (400-1600nm, excluding 475-500nm). When a TGG crystal is placed in a magnetic field, it induces a non-reciprocal rotation of polarization, forming the principle of an optical isolator. This rotation in the polarization plane also enables the creation of various other optical devices such as magneto-optical modulators, circulators, and current measuring transducers.
Specifications:
| Parameter | Example Value/Range |
| Crystal Structure | Cubic system，la3d, a=12.355 |
| Melting Point | ~1725°C |
| Mohs Hardness | ~7.0 |
| Density | 7.13 g/cm3 |
| Thermal Conductivity | ~7.4 W/m/K |
| Thermal Expansion Coefficient | 6.7-7.2 x10-6/K |
| Transmittable Wavelength Range | 400-1600nm，excluding470-500nm |
| Refractive Index | 1.95 @ 1064 nm |
| Verdet Constant | 40 rad/T/m @ 1064 nm 134 rad/T/m @ 633 nm |
| Crystal Orientation | [111]、[100]，±15′ |
| Wavefront Distortion | <λ /8 |
| Extinction Ratio | >30 dB |
| Outer Diameter Tolerance | +0.00 mm/-0.05 mm |
| Length Tolerance | +0.2 mm/-0.2 mm |
| Flatness | <λ/10 @ 633 nm |
| Parallelism | <30″ |
| Perpendicularity | <5′ |
| Surface Finish | 10/5 |
Advantages:
- Large Verdet Constant: Approximately 40 Rad T^-1 m^-1, indicating strong magneto-optical effects.
- Superb Thermal Properties: Thermal conductivity of 7.4 W/m/K, providing excellent thermal management.
- Low Optical Losses: Less than 0.1% per centimeter, ensuring minimal light attenuation.
- High Damage Threshold: Can withstand laser-induced damage thresholds greater than 1 GW/cm².
- Better Performance: Outperforms terbium-doped glasses in high average power fiber lasers due to greater Verdet constant and lower optical losses.
Applications:
- Faraday Rotators: Key component in optical isolators to prevent back reflections and enhance laser performance.
- Magneto-Optical Modulators: Devices that modulate light using magnetic fields for various optical applications.
- Circulators: Used in optical systems to control the direction of light flow.
- Current Measuring Transducers: Devices that measure electrical current by detecting the magnetic field effects on light.
