AgGaS2

Silver Gallium Sulfide (AgGaS2) and Silver Gallium Selenite (AgGaSe2) crystals have recently attained special interest for the middle and deep infrared (IR) applications, due to their large nonlinear optical (NLO) coefficients and high transmission in the IR region. The phase matching and transmission characteristics of AgGaS2 allow 3-wave interactions in the mid and near IR. AgGaS2 has been used as an efficient NLO crystal for 3 - 10 mm IR output, particularly for OPO devices pumped with Nd:YAG laser, frequency mixing of OPO outputs pumped by Ti:Sapphire or Nd:YAG laser, as well as frequency mixing Nd:YAG laser with dye and Ti:Sapphire or other laser sources. AgGaSe2 has also been demonstrated to be an efficient frequency doubling crystal for infrared radiation such as 10.6 mm output of CO2 lasers.

Crystal	AgGaS₂	AgGaSe₂
Crystal structure	Tetragonal	Tetragonal
Cell parameters(Å)	a=5.756, c=10.301	a=5.992, c=10.886
Melting point(^oC)	997	851
Density(g/cm³)	4.702	5.7
Absorption Coefficient(cm^-1) @ 1.064mm @ 10.6mm	0.01 0.6	<0.05 <0.02
Resistance	>10¹²	unavailable
Relative Dielectric Constant e₁₁^s/e₀ @ 25 MHz e₃₃^s/e₀ @ 25 MHz	10 14	10.5 12
Thermal Expansion Coefficient (10^-6/^oC) çê C ^ C	12.5 -13.2	16.8 -7.8
Thermal conductivity(W/cm/^oC)	0.015	unavailable

Crystal	AgGaS₂	AgGaSe₂
Transparency Range(nm)	0.50-13.2	0.78-18.0
Refractive Indices @ 1.064mm @ 5.300mm @ 10.60mm	n_o n_e 2.4521 2.3990 2.3945 2.3408 2.3472 2.2934	n_o n_e 2.7010 2.6792 2.6134 2.5808 2.5912 2.5579
Wavelength @ n_o=n_e(mm)	0.4974	0.811
Thermo-Optic Coefficients d_no/dt(10^-5/^oC) d_ne/dt(10^-5/^oC)	15.4 15.5	~15 ~15
Sellmeier Equations:
AgGaS₂: n_o²(l) = 3.3970 + 2.3982/ (1-0.09311/l²)+2.1640 / (1-950/l²) (l in mm) n_e²(l) = 3.5873 + 1.9533 / (1-0.11066/l²)+2.3391 / (1-1030.7/l²)
AgGaSe₂: n_o²(l) = 4.6453 + 2.2057 / (1-0.1879/l²)+1.8577 / (1-1600/l²) (l in mm) n_e²(l) = 5.2912 + 1.3970 / (1-0.2845/l²)+1.9282 / (1-1600/l²)

Crystal	AgGaS₂	AgGaSe₂
Phase-Matching SHG output range(mm)	1.8-11.2	3.1-12.8
NLO Susceptibilities d36(pm/V)SHG @ 10.64 mm	18	58
Linear Electro-Optic Coefficients g41^T g63^T	4.0،ہ0.2 3.0،ہ0.1	4.5 @ 1.15 mm 3.9 @ 1.15 mm
Damage Threshold(MW/cm²) @ ~ 10ns, 1.064 mm @ ~ 10ns, 10.6 mm	25, surface > 500 bulk	20-30, surface