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Product Introduction
GaSe (gallium selenide) crystals are dark brown, fluorescent flaky crystals with a relative density of 5.03 and a melting point of (960 ± 10) °C. Like GaS, GaSe is a layered semiconductor; as temperature decreases, the maximum photoelectric effect shifts toward shorter wavelengths. As a nonlinear crystal and photoconductor, GaSe is widely used in applications such as generating second harmonics in COۑ lasers, frequency upconversion of COۑ lasers to near-infrared or visible light, optical mixing in the mid-infrared region, and generation of various frequencies within the 5.5–18.0 μm mid-infrared band. Additionally, GaSe crystals serve as terahertz crystals for producing terahertz radiation.
GaSe (gallium selenide crystals) exhibit terahertz oscillations across an exceptionally wide frequency range, extending up to 41 THz. As a negative uniaxial layered semiconductor crystal with a hexagonal structure corresponding to the 62m space group, GaSe has a bandgap width of 2.2 eV at 300 K. Its high damage resistance threshold, significant nonlinear coefficient (54 pm/V), optimal transparency range, and ultra-low absorption coefficient make it an ideal material for broadband electromagnetic wave oscillation in the mid-infrared region. Since broadband terahertz oscillation and detection require laser sources operating below 20 femtoseconds, GaSe-based emission-detection systems achieve performance comparable to or even superior to that of ZnTe systems. By optimizing the thickness of GaSe crystals, frequency selectivity for terahertz waves can be precisely controlled.
Note: The cleavage plane of GaSe (gallium selenide) crystals is (001); consequently, a major limitation in their application lies in their softness and fragility.
GaSe (Gallium Selenide) Crystal Parameters
| Structure | 62m; a=3.74 ; c=15.89 |
| Density | 5.03g/cm3 |
| Moh's hardness | 2 |
| Eg, eV | 2.02 |
| Refraction Index @ 5.3 μm | no=2.8340; ne=2.4599 |
| Refraction Index @ 10.6 μm | no=2.8136; ne=2.4389 |
| Refraction Index @ 0.633 μm | no=2.9365 |
GaSe (Gallium Selenide) crystal transmission spectrum
GaSe crystals, gallium selenide crystal products
| Name of a part | Model | Bore | Crystal thickness | Installation Frame Dimensions |
| GaSe crystal* | GaSe-001-CA7-T0.01 | 7mm | 10um | 25.4mm |
| GaSe crystal | GaSe-001-CA7-T0.03 | 7mm | 30um | 25.4mm |
| GaSe crystal | GaSe-001-CA7-T0.1 | 7mm | 0.1mm | 25.4mm |
| GaSe crystal | GaSe-001-CA7-T0.2 | 7mm | 0.2mm | 25.4mm |
| GaSe crystal | GaSe-001-CA7-T0.3 | 7mm | 0.3mm | 25.4mm |
| GaSe crystal | GaSe-001-CA7-T0.5 | 7mm | 0.5mm | 25.4mm |
| GaSe crystal | GaSe-001-CA7-T1 | 7mm | 1mm | 25.4mm |
*The GaSe crystal is typically packaged in a metal mounting frame with an outer diameter of 1 inch.