Zinc Sulfide (ZnS) Optical Windows
Chenyu Optics manufactures custom Zinc Sulfide (ZnS) optical windows for infrared imaging, multispectral sensing and thermal camera assemblies. IR Grade and Multispectral Grade ZnS are available with AR, BBAR, dual-band AR and DLC coating options.
Zinc Sulfide Optical Windows Overview
Zinc Sulfide (ZnS) optical windows are infrared and multispectral optical components used to protect optical systems while transmitting visible, MWIR and LWIR wavelengths. ZnS is selected when one window material must support broad spectral transmission from approximately 0.4 μm to 12 μm.
Standard IR Grade ZnS is commonly used for thermal imaging systems operating in the 3–5 μm and 8–12 μm atmospheric windows. Multispectral Grade ZnS provides improved visible transmission and reduced scatter, making it suitable for multispectral imaging, visible alignment and infrared observation systems.
Chenyu Optics supports drawing-based ZnS window production for round, square, rectangular and special-shaped components. Available processes include precision polishing, chamfering, edging, AR coating, BBAR coating, DLC protective coating, dimensional inspection and clean optical packaging.
Key Advantages of Zinc Sulfide Optical Windows
Infrared Imaging & Multispectral Use
ZnS windows are suitable for thermal cameras, MWIR and LWIR sensor assemblies, multispectral observation systems and infrared optical modules where broad transmission and environmental stability are required.
Typical Specifications of Zinc Sulfide Optical Windows
| Material | Zinc Sulfide / ZnS |
|---|---|
| Material Grade | IR Grade ZnS / Multispectral Grade ZnS |
| Transmission Range | Approx. 0.4 – 12 μm, depending on grade, thickness and coating |
| Refractive Index | Approx. 2.2 @ 10 μm |
| Density | Approx. 4.09 g/cm³ |
| Knoop Hardness | Approx. 160 kg/mm² |
| Surface Quality | 20-10, 40-20, 60-40 or custom |
| Clear Aperture | ≥ 85%, ≥ 90% or drawing-based |
| Surface Flatness | λ/10, λ/4, λ/2 or custom @ 632.8 nm |
| Parallelism | ≤ 30 arcsec, ≤ 3 arcmin or custom |
| Diameter / Size | Custom round, square, rectangular or special-shaped windows |
| Thickness Tolerance | ±0.1 mm, ±0.05 mm or custom |
| Chamfer | 0.1 – 0.3 mm × 45° or drawing-based |
| Coating Options | Uncoated, AR, BBAR 3–5 μm, BBAR 8–12 μm, dual-band AR, DLC protective coating |
Optical Transmission Characteristics of Zinc Sulfide Optical Windows
Why Choose Chenyu Optics for Zinc Sulfide Optical Windows
Chenyu Optics focuses on custom optical component manufacturing for industrial infrared and precision optical applications. We support tolerance review, drawing-based production, prototype verification and repeat batch supply for customers who require non-standard optical components.
Zinc Sulfide Optical Windows Manufacturing Capability
Precision Polishing
Controlled polishing for flatness, surface quality, edge condition and optical clarity.
Optical Coating
AR, BBAR, dual-band AR and DLC coating support for different infrared wavelength ranges.
Inspection & Packaging
Dimensional inspection, visual quality review, optional inspection records and clean protective packaging.
Custom Manufacturing Options for Zinc Sulfide Optical Windows
Dimensions & Geometry
Round, square, rectangular and special-shaped ZnS windows can be manufactured according to customer drawings, including custom thickness, diameter, edge form and clear aperture requirements.
Surface & Mechanical Quality
Surface quality, flatness, parallelism, clear aperture and chamfer specifications can be selected based on imaging performance, assembly method and environmental requirements.
Coating & Wavelength Design
Uncoated, single-band AR, broadband AR, dual-band AR and DLC protective coatings can be designed for MWIR, LWIR or multispectral applications.
Zinc Sulfide Optical Windows Material Comparison
| Material | Zinc Sulfide (ZnS) | Zinc Selenide (ZnSe) | Germanium | Calcium Fluoride (CaF₂) |
|---|---|---|---|---|
| Transmission | Visible to LWIR, approx. 0.4 – 12 μm | Mid-IR to LWIR, commonly used from 0.6 – 16 μm | Mid-IR to LWIR, commonly used from 2 – 14 μm | UV to MWIR, commonly used from 0.13 – 8 μm |
| Visible Transmission | Available with Multispectral Grade ZnS | Yellow-orange material with visible transmission | Opaque in visible wavelengths | Good visible and UV transmission |
| Mechanical Notes | Good environmental durability for multispectral windows | Softer material; often used in CO₂ laser and IR systems | High density and high refractive index IR material | Lower refractive index; more sensitive to thermal shock |
| Typical Use | Multispectral windows, MWIR/LWIR imaging, thermal sensing | CO₂ laser optics, thermal imaging windows, IR transmission optics | Thermal imaging windows, IR lenses, rugged LWIR systems | UV, visible, NIR and MWIR windows for instruments |
Applications of Zinc Sulfide Optical Windows
Thermal Imaging
MWIR and LWIR cameras, IR sensors and thermal observation systems.
Multispectral Optics
Visible-to-infrared imaging systems requiring broad spectral transmission.
MWIR Systems
Infrared optical assemblies operating in the 3–5 μm wavelength band.
LWIR Systems
Long-wave infrared imaging and sensing systems operating in the 8–12 μm band.
UAV Payloads
Infrared gimbal cameras, airborne imaging modules and lightweight sensor windows.
Spectroscopy
Infrared spectroscopy, gas detection and scientific optical instruments.
Zinc Sulfide Optical Windows FAQ
What is the difference between IR Grade and Multispectral Grade ZnS?
IR Grade ZnS is commonly used for MWIR and LWIR thermal imaging applications. Multispectral Grade ZnS provides improved visible transmission and lower scatter, making it suitable for systems requiring visible-to-infrared performance.
Can ZnS replace ZnSe in infrared optical systems?
ZnS and ZnSe both transmit infrared wavelengths, but they are not always interchangeable. Selection depends on wavelength range, visible transmission requirement, mechanical environment, coating design, component thickness and system budget.
What wavelength range can ZnS optical windows transmit?
ZnS can transmit from approximately 0.4 μm to 12 μm, depending on material grade, thickness, coating design, surface quality and measurement conditions.
Which coating is recommended for MWIR or LWIR ZnS windows?
For MWIR systems, AR or BBAR coating around 3–5 μm is commonly used. For thermal imaging systems, AR or BBAR coating around 8–12 μm is often selected. Dual-band coating can be considered when both bands are required.
Is DLC coating available for outdoor or harsh-environment ZnS windows?
Yes. DLC protective coating can be applied when the external surface requires improved abrasion resistance and environmental protection. The coating design should be reviewed together with the operating wavelength and system environment.
Can you manufacture custom ZnS window sizes and shapes?
Yes. Chenyu Optics manufactures custom diameters, thicknesses, rectangular windows, square windows and drawing-based special shapes. Clear aperture, chamfer, parallelism and coating requirements can be specified according to the drawing.
What information should I provide for quotation?
Please provide material grade, size, thickness, clear aperture, surface quality, flatness, parallelism, coating requirements, quantity, drawing and application wavelength range if available.
Where can I find additional industry reference information about Zinc Sulfide?
Additional optical material reference information is available from Edmund Optics optical substrate resources. Chenyu Optics can review the final ZnS specification according to your drawing, wavelength range and operating environment.
Related Products for Zinc Sulfide Optical Windows
Need Custom Zinc Sulfide Optical Windows?
Send us your drawing, wavelength range, size, thickness, coating requirements and quantity. Chenyu Optics will review the optical and mechanical specifications and provide a suitable ZnS window manufacturing suggestion.