CVD ZnSe windows are made from zinc selenide (ZnSe) material synthesized through chemical vapor deposition (CVD). ZnSe is a yellow-transparent polycrystalline material known for its high purity, strong environmental adaptability, and ease of processing. It exhibits low optical transmission loss and excellent transmittance, making it particularly suitable for high-power laser systems.
CVD ZnSe windows exhibit high transmittance in the 600 nm to 16 μm wavelength range, making them well-suited for infrared spectroscopy applications.
Material Characteristics:
High Purity: The material boasts high purity, strong environmental adaptability, and ease of processing, which are essential for a high-performance zinc selenide window.
Low Absorption: It features a low absorption coefficient of less than 0.0005 cm^-1 at a wavelength of 10.6 μm, a key advantage of CVD ZnSe materials.
Thermal Shock Resistance: The material has excellent thermal shock resistance, making it ideal for high-power CO2 laser systems.
Low Hardness: Due to its relatively low hardness, ZnSe is prone to scratches and typically requires a high-hardness anti-reflective coating for protection.
| Physical characteristics | ||
| Density (@300K, g/cm³) | 5.27 | |
| Fusing point (K) | 1.798 | |
| Thermal conductivity @298K, J/(K *m*c) | 18 | |
| Coefficient of thermal expansion | @273K | 7.1*10-6 |
| 1/K | @373K | 7.8*10-6 |
| @473K | 8.3*10-6 | |
| Thermal capacity (@298K, J/(g*K) | 0.339 | |
| Hardness | Knoop, with 50g indenter, Kg/mm² | 120 |
| Vickers, with1kg indenter, kg/mm² | 112 | |
| Young's modulus (E), Gpa | 67.2 | |
| Bulk modulus (K), Gpa | 40 | |
| Surface elastic limit, mpa | 55.1 | |
| Optical characteristic | ||
| Thermo-optical coefficient (dn/dT) @1.06um @298-358K, 1/K | 6.1*10-5 | |
| Restrahlen peak, (mm) | 45.7 | |
| Reflection loss @10.6um (both surfaces). % | 29.1 | |
| Reflection inhomogeneity (dn/n) @0.633um, < | 3*10-5 | |
| Specifications | Commercial spec. | High precision spec. |
| Dimension | 5mm~350mm | |
| Dimension tolerance | ±0.1mm | ±0.05mm |
| Focal length tolerance | ±2% | ±1% |
| Surface quality | 60/40 | 40/20 |
| Centration | < 3 arc min | <1arc min |
| Surface figure | 3λ | 2λ |
| Surface irregularity | 1/4λ | 1/10λ |
| Clear aperture | >85% of dim | >90% of dim |
| Bevel | <0.2mm x 45deg | <0.1mm x 45deg |
| Coating | AR/AR 7-12um / 10.6um / 2-13um | |
| Material | Diameter （mm） | Thickness （mm) | Coating |
| CVD ZnSe | 12.7 | 2.4 | AR/AR 10.6um |
| CVD ZnSe | 12.7 | 2.5 | AR/AR 10.6um |
| CVD ZnSe | 19.05 | 2 | AR/AR 10.6um |
| CVD ZnSe | 20 | 2 | AR/AR 10.6um |
| CVD ZnSe | 20 | 3 | AR/AR 10.6um |
| CVD ZnSe | 25 | 3 | AR/AR 10.6um |
| CVD ZnSe | 38.1 | 3 | AR/AR 10.6um |
High-Power CO2 Lasers:
Due to its high purity, strong environmental adaptability, ease of processing, and low optical transmission loss, CVD ZnSe is the optimal window material for industrial high-power CO2 lasers.
Infrared Applications:
CVD ZnSe excels in infrared applications, making it suitable for thermal imaging, FLIR (Forward-Looking Infrared) systems, and medical systems. This zinc selenide window material features a low absorption coefficient and high resistance to thermal shock, making it widely used in these systems, while caf2 window materials are often chosen for applications requiring broader transmission from ultraviolet to infrared wavelengths.
Military Equipment:
CVD ZnSe is also employed in advanced missile, aircraft, tank, and warship infrared search and targeting systems, serving as a key material for lenses, prisms, and other optical components.
