AgGaS2 crystals
Main features
- Unique non-linear properties across the transmission range 0.5 to 12 μm
- Low optical absorption and scattering
- Short wavelength transparency
Application examples
- Frequency mixing in the middle IR region from 4.0 to 18.3 µm
- Second harmonic generation and up-conversion for CO2 lasers
- Tunable OPO for solid state lasers
- Description
- Properties
- Specifications
Silver Thiogallate (AgGaS2) has been demonstrated as an efficient frequency doubling crystal for infrared radiation as well an excellent crystal for non-linear three-wave interactions. AgGaS2 is transparent from 0.53 to 12 µm.
AgGaS2 based optical parametric oscillators (OPO's) can produce continuously tunable radiation over a wide range of wavelengths in the infrared spectral range. Its high short wavelength transparency beginning at 550 nm is used in OPOs pumped by Nd:YAG laser. Using 2050 nm pump laser, an optimally designed AgGaS2 OPO is tunable from about 2.5 to 12.0 µm. The output range can be extended by the sum or difference frequency mixing (SFM/DFM). This crystal has a high non-linear coefficient, high damage threshold, and a wide transmission range. It also has low optical absorption and scattering, low wavefront distortion. AgGaS2 has the highest figure of merit for non-linear interactions in the near and deep infrared.
| Single crystal | AgGaS2
|
| Crystal Structure
|
42m |
| Lattice(Cell) Parameters
|
a=5.757 Å, c=10.302 Å
|
| Transmission Range
|
0,5-12 µm
|
| Refractive Index
@1,06 µm @3 µm @5,3 µm @10,6 µm @12 µm |
no=2.4521; ne=2.3990 no=2.4080; ne=2.3545 no=2.3945; ne = 2.3408 no = 2.3472; ne=2.2934 no=2.3266; ne&=2.2716 |
| Non-linear coefficient @10.6 µm
|
d36=11,1 pm/V
|
| Optical damage threshold @10,6 µm, 150 ns
|
>10 MW/cm2 |
| Optical damage threshold @1,06 µm, 10 ns
|
>350 MW/cm2 |
| Thermal expansion coefficient
parallel to c-axis perpendicular to c-axis |
12.5×10-6×°C-1 -13.2×10-6×°C-1 |
| Mohs hardness
|
>3 |
| AgGaS2 crystals | |
|---|---|
| Clear aperture | 85% |
| Face dimensions tolerance | +0/-0,2 mm |
| Thickness tolerance | ±0,2 mm |
| Parallelism error | <30 arcsec |
| Protective chamfers | <0,2 mm at 45° |
| Coatings | Uncoated |
| Surface quality | 20-10 S-D |
| Wavefront distortion | <λ/[email protected],8 nm |
| Laser induced (material) damage threshold | >350 MW/cm2@1064 nm, 10 ns |
