Zinc Selenide Window

Zinc selenide windows separate an optical system's interior from its surroundings and protect internal devices. Features include high transmission, strong antireflection performance, and thermal stability. Visible/IR transmission is high, with low reflection and absorption. They serve as transmitting or reflecting elements in lidar, optical sensors, spectrometers, and related equipment. Various sizes and specifications meet different needs, including round, rectangular, wedged, apertured, and stepped windows. Available coatings include reflective, antireflection, filtering, beamsplitting, polarization, and metallization. Hechen Crystal Technology has precision manufacturing and inspection equipment including ultraprecision single-point diamond turning, Taylor Hobson profile measurement/analysis, ZYGO flat/spherical interferometers, Fuji interferometers, spectrophotometers, centration instruments, and goniometers. ZnSe is chemically inert, high-purity, environmentally adaptable, and easy to machine. Low transmission loss and good transparency make it a preferred high-power CO2 laser optical material. Uniform, consistent refractive index also suits protective windows and optics in forward-looking infrared (FLIR) thermal imagers. It is widely used in windows/lenses for medical devices, thermal-radiation meters, and IR spectrometers. ZnSe crystals mainly produce IR-transmitting components and instruments. Transmission from 0.5-15μm makes them suitable for IR lenses, laser windows, and thermal imagers. Ordinary ZnSe versus CVD ZnSe. I. Materials. Ordinary ZnSe is a transparent yellow polycrystalline material transmitting 0.5–15μm, with excellent mid/far-IR transmission, such as CO₂ lasers at 10.6μm. Its hardness is low, approximately 2/3 that of multispectral ZnS, making it scratch-prone; hard antireflection coatings improve durability. CVD ZnSe is chemically vapor-deposited with high structural uniformity and extremely low impurity absorption/scattering for high-power lasers. Its transmission extends to 0.5–22μm, with high thermal-shock resistance and environmental stability. II. Process/performance. CVD synthesis reaches 99.9996% purity and refractive-index nonuniformity below 3ppm at 633nm for consistent performance. Dense, strongly inert, nonhygroscopic material suits demanding medical or industrial thermometry environments. III. Optical comparison. Transmission: ordinary ZnSe 0.5–15μm, CVD ZnSe 0.5–22μm. Bulk absorption at 10.6μm: ordinary ZnSe low but unquantified, CVD ZnSe ≤0.0005 cm⁻¹. Thermal-shock resistance: ordinary relatively high, CVD excellent. IV. Applications. High-power CO₂ lasers use low-absorption, high-damage-threshold CVD ZnSe in windows, lenses, and mirrors. For multispectral systems, the source states UV-to-far-IR transmission for thermal imaging, gas analysis, and spectrometers. Industrial/medical uses include thermometry windows, IR-sensor filters, and laser-treatment optics. V. Processing/customization. CVD ZnSe can form round, wedged, rectangular, and irregular apertured windows with tolerances down to ±0.1mm and subnanometer roughness. Custom transmission-enhancing/antireflection coatings improve band-specific transmission and durability. VI. Summary. Optimized CVD synthesis greatly improves uniformity and environmental adaptability for precise, stable IR laser systems. Ordinary ZnSe remains competitive in cost-sensitive applications but relies on coatings to compensate for mechanical limitations.

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