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Introduction
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
Basic Properties:
|
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) |
Specification:
| 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. |
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