Non-linear Crystal Gallium Selenide (GaSe)
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terahertz crystal
Another material which is very suitable for SHG in the mid-IR is Gallium Selenide (GaSe) non-linear optical single crystal, combining a large non-linear coefficient, a high damage threshold and a wide transparency range. The frequency-doubling properties of GaSe were studied in the wavelength range between 6.0 µm and 12.0 µm. GaSe has been successfully used for efficient SHG of CO2 laser (up to 9% conversion); for SHG of pulsed CO, CO2 and chemical DF-laser (l = 2.36 µm) radiation; upconversion of CO and CO2 laser radiation into the visible range; infrared pulses generation via difference frequency mixing of Neodymium and infrared dye laser or (F-)-centre laser pulses; OPG light generation within 3.5–18 µm; terahertz (T-rays) radiation generation. It is impossibile to cut crystals for certain phase matching angles because of material structure (cleave along (001) plane) limiting areas of applications.

 • Wei Shi, Yujie J. Ding, Nils Fernelius, Konstantin Vodopyanov. Efficient, tunable, and coherent 0.18 - 5.27-THz source based on GaSe crystal: erratum. Optics Letters, (2003) v. 28, 2, 136-136
 • R. A. Kaindl, F. Eickemeyer, M. Woerner, T. Elsaesser. Broadband phasematched difference frequency mixing of femtosecond pulses in GaSe: experiment and theory. Appl. Phys. Lett. 75 (1999) 1060-1062
 • K. L. Vodopyanov. Parametric generation of tunable infrared radiation in ZnGeP2 and GaSe pumped at 3 µm. JOSA B, 1993, 10, 9, 1723

Transparency range, µm 0.62  20
Point group 6m2
Lattice parameters a = 3.74, c = 15.89 Å
Density, g/cm3 5.03
Mohs hardness 2
Refractive indexes:
at 5.3 µm no= 2.7233, ne= 2.3966
at 10.6 µm no= 2.6975, ne= 2.3745
Non-linear coefficient, pm/V d22 = 54
Walk off 4.1° at 5.3 µm
Optical damage threshold, MW/cm2 28 (9.3 µm, 150 ns); 0.5 (10.6 µm, in CW mode); 30 (1.064 µm, 10 ns)

* Unfortunately it is impossibile to cut crystals for certain phase matching angles because of material structure (cleave along (001) plane).
We supply GaSe 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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