logo.jpg High Technologies Laboratory
cross.gif line.gif
About Contacts Products AgGaSe2 AgGaS2 Ag Ga 1-x In x Se 2 Projectsdot.gif
line.gif
dot.gif AgGaS2 dot.gif
Structural and Physical Properties
Crystal symmetry and class Tetragonal, D2d
Space group D122d
Cell parameters (A) a = 5.742,c = 10,305
Melting points (oC) 980
Optical homogeneity Dn < 1*10-4
Density (gram/cm3) 4.58
Absorption coefficient
(cm -1)

< 0.005
Optical and NLO Properties
Optical transmission ( mm ) 0.47 to 12.5
Energy gap (eV) 2.8
Isotropic wavelength ( mm ) 0.497

Laser damage threshold
( t = 10 ns, l = 1.06 mm) (MW/cm2) 20 at surface
Dispersion of refractive indices
(Experimental values)
l (mm) no ne
0.53 2.6418 2.6145
0.65 2.5417 2.4941
1.064 2.4489 2.3952
2.0 2.4131 2.3594
10.6 2.3449 2.2908
Nonlinear optical coefficients:
d36 (10.6 mm) = 0.15 d36 ( GaAs ) = 13.4 pm/V
dooe = d36 sin q sin 2j
deoe = doee = d36 sin 2q cos 2j

Dispersion of refractive indices ( Sellmeier equations, l in mm )
n2o = 4.4368659 + 541.97177 / ( 400.0 + l2 ) - 0.21334425 / ( 0.10173910 - l2 );
n2e = 4.1704137 + 550.23080 / ( 400.0 + l2 ) - 0.19289371 / ( 0.13312863 - l2 ).

The results of the experiments with AgGaS2 element
Pump wavelength (mm) 1.06
30 ps mode-locked output wavelength (mm) 4 - 10
Quantum conversion efficiency (%)
2.8 ( l = 5.2 mm)
1.6 ( l = 6.3 mm)
0.6 ( l = 7.1 mm)

Application

The AgGaS2 crystals are used for frequency doubling and three-frequency mixing. The parametric oscillators on the base of those crystals can produce the continuously tunable wavelength of radiation in the spectral range from 1.0 to 10 mm with suitable pump laser.High quality of nonlinear AgGaS2 elements and their big length make it possible to achieve the high conversion efficiency. The parametric generation in AgGaS2 crystals being pumped by a single picosecond pulse of a Nd3+: YAG laser (1.064 mm) has been investigated in 2.2 - 7.4 mm spectral range. The higher conversion efficiency than reported before (for optical parametric oscillators with picosecond pulse length in this spectral range) has been achieved due to non-collinear two-crystal configuration.On the base of one AgGaS2 element the two-pass OPO has been realized. This device has some advantages in comparison with two-crystal OPO without of losing the conversion efficiency.

up about us contact us projects