AgGaSe2, AgGaS2 are nonlinear optical crystals, which have gained tremendous interest for the middle and deep infrared applications due to their unique features. The crystals have large effective optical nonlinearity, wide spectral and angular acceptance, broad transparency range, noncritical requirements for temperature stabilization and vibration control, are well mechanically processed. AgGaSe’s useful transmission ranges lying within 0.9-16μm and wide phase matchability provides excellent potential for OPO applications when pumped by variety of currently available lasers. AgGaS2 high short wavelength transparency edging at 550nm has been used in OPOs pumped by Nd:YAG laser; in numerous difference frequency mixing experiments using diode, Ti:Sapphire, Nd:YAG and IR dye lasers covering 3-12 µm range; direct infrared countermeasure systems, and SHG of CO2 laser| AgGaSe2 | AgGaS2 | AgGaSe2 | AgGaS2 | ||||
| Crystal Symmetry | Tetragonal | Tetragonal | Optical transmission,μm | 0.73÷18 | 0.5÷12 | ||
| Point Group | 42 m | 42 m | Indices of refraction at | ||||
| Lattice ConstantsΛ | a | 5.9901 | 5.757 | 1.06μm | no | 2.7005 | 2.4508 |
| c | 10.8823 | 10.305 | ne | 2.6759 | 2.3966 | ||
| Density:g/cm3 | 5.71 | 4.56 | 5.3μm | no | 2.6140 | 2.5823 | |
| Laser damage threshold | ne | 2.5823 | 2.3421 | ||||
| 25 MW/cm2 at 50ns 2.05μm | 25 MW/cm2 at 20ns 1.06μm | 10.6 μm | no | 2.5915 | 2.5915 | ||
| ne | 2.5915 | 2.5915 | |||||
| Nonlinearity pm/V | 43 | 31 | |||||
| Phase matching angle for Type 1 SHG at 10.6 μm | 55° | 67° | Absorption Coefficient cm-1 at | 1.06μm | <0.02(9) | <0.02 | |
| Walk-off angle at 5.3 μm | 0.67° | 0.85° | 2.5μm | <0.01 | 0.01 | ||
| Melting point °C | 851 | 998 | 5.0μm | <0.01 | 0.01 | ||
| Thermal Expansion Coefficient 10-6/°K |  |
23.4 | 12.5 | 7.5μm | -//- | 0.02 | |
 |
23.4 | -13.2 | 10.0μm | -//- | <0.6 | ||
| Sellmeier equations | |||||||
| AgGaSe2 | no2=6.8507+0.4297/(λ2-0.15840)-0.00125λ2 | ||||||
| ne2= 6.6792+0.4598/(λ2-0.21220)-0.00126λ2 | |||||||
| AgGaS2 | no2=3.3970+2.3982/(1-0.09311/λ2)+2.1640/(1-950.0/λ2) | ||||||
| ne2=3.5873+1.9533/(1-0.11066/λ2)+2.3391/(1-1030.7 /λ2) | |||||||
| Dimension tolerance | (W ± 0.1 mm) x (H ± 0.1 mm) x (L +/- 0.2 mm) |
| Transmitting wavefront distortion: | l/8 @ 633 nm |
| Clear aperture: | > 90% central area |
| Flatness: | l/8 @ 633 nm |
| Scratch/Dig code: | 10/5 to MIL-O-13830A |
| Parallelism: | better than 20 arc seconds |
| Perpendicularity: | 5 arc minutes |
| Angle tolerance: | Dq < ±0.5°, Df < ± 0.5° |
| AR coating: | R< 0.1% at 1064nm and R<0.4% at 532 nm. |
| Quality Warranty Period: | one year under proper use. |