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High values
of laser damage threshold and conversion efficiency allow to use Mercury
Thiogallate HgGa2S4 (HGS) non-linear crystals
for frequency doubling and OPO/OPA in the wavelength range from 1.0
to 10 µm. It was established that SHG efficiency of CO2
laser radiation for 4 mm length HgGa2S4 element
is about 10 % (pulse duration 30 ns, radiation power density 60 MW/cm2).
The high conversion efficiency and wide range of radiation wavelength
tuning allows to expect that this material may compete with AgGaS2,
AgGaSe2, ZnGeP2 and GaSe crystals in spite of
the considerable difficulty of big size crystals growth process.
APPLICATIONS:
| • Generation
second harmonics on CO and CO2 - lasers |
• Different
frequency generator to middle infrared regions. |
| • Optical
parametric oscilator |
• Frequency mixing in the middle IR region |
Literature: F. Rotermund, V. Petrov and F. Noack, Difference-frequency
generation of intense femtosecond pulses in the mid-IR (4-12 µm)
using HgGa2S4 and AgGaS2. Opt. Commun.
185 (2000) 177-83 |
MAIN
PROPERTIES:
| Transparency
range, µm |
0.55
- 13.00 |
| Negative
uniaxial crystal |
no
> ne |
| Point
group |
4 |
| Mohs
hardness |
3 - 3.5 |
| Density,
g/cm3 |
4.95 |
| Energy
gap, eV |
2.34 |
| Dispersion
of refractive indices (Experimental values): |
|
at 0.5495
µm |
no
= 2.6592; ne = 2.5979 |
| at 0.6500
µm |
no
= 2.5796; ne = 2.5264 |
| at 1.0760
µm |
no
= 2.4774; ne = 2.4324 |
| at 3.5400
µm |
no
= 2.4386; ne = 2.3979 |
| at 11.000
µm |
no
= 2.3690; ne = 2.3290 |
| Non-linear
coefficients |
d36
(1.064 mm) = 1.8 d36 ( AgGaS2 )
± 15% = (35.2 ± 5.3 ) pm/V |
| |
d31
(1.064 mm) = 0.6 d36 ( AgGaS2 )
± 15% = (11.7 ± 1.8 ) pm/V |
| Optical
damage threshold, MW/cm2 |
60 -
90 at surface (1064nm, 10 ns) |
We supply HGS optical
elements made according to customers' order.
|