|
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. AgGaS2
has also been demonstrated to be an efficient frequency doubling crystal
for infrared radiation such as 10.6 mm output of CO2
lasers.
|
Structure and
Physical Properties
|
|
|
|
AgGaS2
|
AgGaSe2
|
| Crystal Structure |
Tetragonal
|
Tetragonal
|
| Cell
Parameters (Å) |
a=5.756, c=10.301
|
a=5.992, c=10.886
|
| Melting Point(°C) |
997
|
581
|
| Density
(g/cm3) |
4.702
|
5.700
|
Absorption Coefficient(cm-1)
@ 1.064 mm
@ 10.6 mm |
0.01
0.6
|
< 0.05
< 0.02
|
| Resistance |
>1012
|
unavailable
|
Relative Dielectric Constant
e11s/eo
@ 25 MHz
e11s/eo
@ 25 MHz |
10
14
|
10.5
12.0
|
Thermal Expansion Coefficient
(10-3/
deg;C) ||C
^C |
+12.5
-13.2
|
+16.8
-7.8
|
| Thermal
Conductivity (W/cm/ °C) |
0.015
|
unavailable
|
|
|
Linear Optical
Properties
|
|
|
|
AgGaS2
|
AgGaSe2
|
| Transparency Range(nm) |
0.50-13.2
|
0.78-18.0
|
Relative Indices
@ 1.064mm
@ 5.300mm
@ 10.60mm |
no
2.4521
2.3945
2.3472
|
ne
2.3990
2.3408
2.2934
|
no
2.7010
2.6134
2.5912
|
no
2.6792
2.5808
2.5579
|
| Wavelength @no=ne(mm) |
0.4974
|
0.811
|
Thermo-Optic Coefficient
dno/dt(10-5/°C)
dne/dt(10-5/°C) |
15.4
15.5
|
~15
~15
|
| Sellmeier Equations |
AgGaS2:
no2
(l)=
3.3970 + 2.3982/(1 - 0.09311/l2)
+ 2.1640/(1 - 950/l2)
ne2
(l)=
3.5873 + 1.9533/(1 - 0.11066/l2)
+ 2.3391/(1 - 1030.7/l2) |
AgGaSe2:
no2
(l)=
4.6453 + 2.2057/(1 - 0.1879/l2)
+ 1.8577/(1 - 1600/l2)
ne2
(l)=
5.2912 + 1.3970/(1 - 0.2845/l2)
+ 1.9282/(1 - 16007/l2) |
|
|
Nonlinear Optical
Properties
|
|
|
|
AgGaS2
|
AgGaSe2
|
| Phase-Matching SHG 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
g41T
g63T |
4.0+/-0.2
3.0+/-0.1
|
4.5@1.15mm
3.9@1.15mm
|
Relative Indices
@ ~ 10ns, 1.064mm
@ ~ 10ns, 10.6mm |
25,surface
>500 bulk
|
20-30,surface
|
|
|
