Non-linear Crystal Silver Thiogallate (AgGaS2 or AGS)
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Silver Thiogallate (AgGaS2 or AGS) is transparent from 0.53 to 12 µm and has been demonstrated to be an efficient frequency doubling crystal for infrared radiation, such as the 10.6 µm output of CO2 lasers. Although nonlinear optical coefficient is the lowest among the above mentioned infrared crystals, its high short wavelength transparency edging at 550 nm is 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.
   With suitable pump lasers, AgGaS2 optical parametric oscillators (OPO's) can produce continuously tunable radiation over a wide range of wavelengths in the infrared. Using a 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. Among commercially available crystals, AgGaS2 has the highest figure of merit for non-linear interactions in the near and deep infrared. The availability of this crystal has stimulated new activities exploiting its interesting properties. Potential applications include wavelength selectable medical procedures and a wide variety of spectroscopic applications. It is useful for high performance IR waveplates. It has also been shown as an excellent crystal for non-linear three-wave interactions.

  • Generation second harmonics on CO and CO2 - lasers
  • Optical parametric oscilator
  • Different frequency generator to middle infrared regions up to 12 mkm.
  • Frequency mixing in the middle IR region from 4.0 to 18.3 µm
  • Tuneable solid state lasers (OPO pumped by Nd:YAG and others lasers operating in 1200 to 10000 nm region with efficiency 0.1 to 10 %)
  • Optical narrow-band filters in the region near isotropic point (0.4974 m at 300 K), transmission band being tuned at temperature variation
  • Up-conversion of CO2 laser radiation image into near-IR or visible region by using/ or use of Nd:YAG, ruby or dye lasers with efficiency up to 30 %

Transparency range, µm 0.47 - 13
Point group 4m2
Lattice parameters, Å a = 5.757, c = 10.311 Å
Density, g/cm3 4.58
Mohs hardness 3.0 - 3.5
Refractive indexes:
at 1.06 µm no = 2.4521; ne = 2.3990
at 3.0 µm no = 2.4080; ne = 2.3545
at 5.3 µm no = 2.3945; ne = 2.3408
at 10.6 µm no = 2.3472; ne = 2.2934
at 12 µm no = 2.3266; ne = 2.2716
Non-linear coefficient at 10.6 µm, pm/V d36 = 12.5 pm/V
Optical damage threshold at 10.6 µm, 150 ns, MW/cm2 10 - 20
Walk off 0.76° at 5.3 µm
Thermal expansion coefficient  
parallel to c-axis 12.5 x 10-6 x C-1
perpendicular to c-axis -13.2 x 10-6 x C-1

We supply AGS optical elements made according to customers' order.

I N Q U I R Y    F O R M :

Quantity of elements:

For example: SHG@1064; SFG@800+267->200; DFG@780-842->10600; OPO@355->460÷560+960÷1150; etc.
polished sites:

 a-b b-c a-c
or d  
Type & angles:
 I    II         angles:  theta  , phi
For example:
10.0 +/- 0.1

For example: p-coating, ARC s1/s2 1064 R<0.25%; ARC s1/s2 1064 R<0.25%+532<0.5%;
BBAR s1/s2 1064 R<1%+3÷10<5% etc.
a = mm;
c = mm
b     = mm or
dia. = mm;
This field is for additional information such as application,
comments, add. requirements etc.

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