Zinc Selenide ZnSe Windows Datasheet


Zinc Selenide (ZnSe) windows are highly regarded in the optical industry for their exceptional performance across a wide infrared spectrum. These windows are crafted from a chemically vapor-deposited synthetic Zinc Selenide, known for its high optical transmission and low absorption coefficients, making it an ideal material for a variety of demanding infrared applications.

Key Features and Specifications:

  • Broadband Infrared Transmission: ZnSe windows exhibit excellent transmittance from 0.6 to 20 microns, covering the full visible to far-infrared range. This makes them suitable for high-power IR lasers and other sophisticated infrared applications.
  • High Durability and Resistance: Zinc Selenide is a robust material that resists thermal shock and is stable under a variety of environmental conditions. This durability makes ZnSe windows suitable for both indoor and outdoor applications.
  • Low Dispersion: With its low dispersion properties, ZnSe minimizes chromatic aberration in optical systems, enhancing system performance and image quality.
  • Customizability: ZnSe windows can be precision fabricated to various sizes, thicknesses, and shapes, and can be coated with anti-reflective coatings to further enhance their optical performance.


  • CO2 Laser Systems: ZnSe is commonly used in the optics of CO2 lasers due to its high resistance to thermal shock and its ability to withstand high energy densities.
  • Thermal Imaging: Ideal for forward-looking infrared (FLIR) systems and other thermal imaging applications, where clear and precise imaging is crucial.
  • Spectroscopy: Used in spectroscopic components where high precision and minimal optical distortion are required.
  • Medical Applications: ZnSe windows are used in various medical imaging techniques, including diagnostic systems that rely on infrared spectroscopy.


  • High Optical Clarity: Ensures superior image quality and optimal performance in precision imaging and laser applications.
  • Versatility: Suitable for a wide range of IR applications due to its excellent transmissive properties across a broad wavelength spectrum.
  • Customization Flexibility: Available in a variety of specifications to meet the unique demands of different optical systems.

General Specification

Type: Protective Window

  • Material: Zinc Selenide (ZnSe)
  • Clear Aperture: 90% of diameter
  • Density: 5.27 g/cm³
  • Coefficient of Thermal Expansion (CTE): 7.57 x 10^-6 /°C
  • Knoop Hardness: 120 kg/mm²
  • Poisson’s Ratio: 0.28
  • Index of Refraction (n_d): 2.631
  • Surface Flatness (P-V): λ/10 at 10.6µm
  • Wavelength Range (nm): 600 – 18000

Dimensional Tolerances

  • Diameter Tolerance: +0.0, -0.25 mm
  • Thickness Tolerance: +0.1, -0.25 mm

Surface Characteristics

  • Surface Quality: 40-20 scratch & dig
  • Surface Irregularity: λ/2 per inch @ 633 nm over clear aperture

Alignment & Geometry

  • Edges: Fine Ground
  • Parallelism (arcmin): <1

Coatings (Available Options for ZnSe)

  • BBAR (Broadband Anti-Reflective): Effective for 0.8 to 2.5 µm, 3 to 5 µm, 1 to 5 µm, 8 to 12 µm, and 3 to 12 µm spectral regions.
  • Single Wavelength AR Coating: 10.6µm R ≤ 0.5% per surface.
  • Other Specialized Wavelength Bands: Possible within the 0.6 to 16 µm range.

Zinc Selenide (ZnSe) windows stand out in the field of infrared optics for their superior optical qualities and adaptability to a wide range of demanding applications. Whether used in industrial, military, medical, or scientific settings, ZnSe windows offer reliable performance and high precision, making them a preferred choice for professionals around the globe.

Specific Properties:

Optical Properties

  • Transmission Range: 0.6 to 21.0 microns
  • Refractive Index: 2.4028 at 10 microns
  • Reflection Loss: 31.11% at 10.6 µm (2 surfaces)
  • Index of Absorption: 0.0005 cm^-1 at 10.6 microns
  • Restrahlen Peak: 45.7 microns
  • dN/dT: +61 x 10^-6/°C at 10.6µm at 298K
  • dN/dμ = 0: 5.5µm

Physical Properties

  • Density: 5.27 g/cm³
  • Melting Point: 1525°C (dissociates about 700°C)
  • Thermal Conductivity: 18 Wm^-1K^-1 at 298K
  • Thermal Expansion: 7.1 x 10^-6/°C at 273K
  • Hardness: Knoop 120 with 50g indenter
  • Specific Heat Capacity: 339 J kg^-1K^-1
  • Young’s Modulus (E): 67.2 GPa
  • Bulk Modulus (K): 40 GPa
  • Apparent Elastic Limit: 55.1 MPa (8,000psi)
  • Poisson’s Ratio: 0.28

Chemical Properties

  • Solubility: 0.001 g/100g water
  • Molecular Weight: 144.33
  • Class/Structure: HIP polycrystalline cubic, ZnS, F43m

About Coating Quality

  • Adhesion Test Compliant with MIL-C-675C military standards, an adhesion test involved applying a tape that meets LT-90 specifications onto the lens film layer. The tape was affixed fully and then removed vertically. This procedure was performed three times, resulting in no blistering or peeling.
  • Temperature Test In line with MIL-C-675C specifications, test pieces were subjected to temperatures of -62±1℃ and 71±1℃. After maintaining them at room temperature (16℃~32℃) for two hours, the adhesion test was repeated, confirming no film detachment.
  • Abrasion Resistance Test Conforming to MIL-C-675C and CCC-C-440 standards, the abrasion resistance test involved a gauze tester applying a minimum force of 1.0 lbs (0.45 kg) to the film. This was repeated 25 times with gauze widths of 1/4 inch (6.4mm) and 3/8 inch (9.5mm), ensuring no damage occurred to the film surface.
  • Humidity Test Under MIL-C-675C criteria, the test piece was placed in a controlled temperature and humidity chamber set to 49 ±2℃ and 95%~100% humidity for 24 hours. The film remained intact, with no peeling, scratches, or other defects.
  • Solvent and Cleaning Testing Following MIL-C-675C specifications, test pieces were exposed to room temperature conditions (16℃~32℃) and tested with acetone and alcohol for at least 10 minutes each. After air drying and subsequent cleaning with a cotton cloth soaked in alcohol, the film surface showed no signs of peeling or scratches.
  • Salt Spray Test After 100 hours in a 35°C environment with a 5% saltwater concentration, the film showed no signs of damage.

Shapeoptics offers a comprehensive range of materials and advanced equipment for custom and OEM optical components, leveraging over 20 years of expertise in manufacturing lenses, prisms, windows, and more. We utilize high-quality materials like UV and IR grade fused silica, Germanium, and ZnSe, among others. Our state-of-the-art techniques and equipment minimize waste and optimize delivery times. Our in-house capabilities include standard and custom coatings across the UV-NIR spectrum, ensuring high quality and compliance with all industry standards. For precision and reliability in optics, contact Shapeoptics for your next project.


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