What Is a Zinc Sulfide Lens?
A Zinc Sulfide (ZnS) lens is an optical component manufactured from Zinc Sulfide crystal, a compound with excellent infrared transmission properties and high durability. These lenses are commonly used in infrared imaging, thermal cameras, FLIR systems, and optical sensors operating in the 3 to 12 µm wavelength range.
At Bote Optical, we offer custom ZnS lenses tailored to your optical design needs. Whether you need aspheric, plano-convex, or dome lenses, our engineering team delivers precision and performance with global export support from our Singapore HQ.
What Is Zinc Sulfide (ZnS)?
Zinc Sulfide, chemically written as ZnS, is a naturally occurring compound composed of zinc and sulfur. It is commonly used in the optical industry due to its:
- High infrared transmission
- Low absorption in the 8–12 µm range
- Good mechanical strength
- Thermal and chemical stability
🔬 Other Names:
- ZnS
- Zinc Blende (natural form)
- Multispectral ZnS (CVD ZnS)
Zinc Sulfide Optical Properties
| Property | Value |
|---|---|
| Chemical Formula | ZnS |
| Transmission Range | 0.4 – 14 μm (Multispectral ZnS) |
| Refractive Index @ 10.6 μm | ~2.2 |
| Density | 4.09 g/cm³ |
| Hardness (Knoop) | ~160 |
| Thermal Expansion Coefficient | ~6.5 × 10⁻⁶ /°C |
| Melting Point | ~1700°C |
✅ High transmission in LWIR (8–12 µm)
✅ Compatible with CO₂ laser wavelengths (10.6 µm)
✅ Ideal for high-power laser and thermal imaging applications
Types of Zinc Sulfide Lenses We Offer
| Lens Type | Description |
|---|---|
| Plano-Convex (PCX) | Focuses infrared light to a point; used in IR imaging systems |
| Double-Convex (DCX) | Used for multi-element IR assemblies |
| Aspheric Lenses | Reduces spherical aberration for high-precision optics |
| Dome Lenses | Ideal for protective windows in aerospace and military IR sensors |
| Customized Shapes | Per your drawings: meniscus, concave, or off-axis parabolic profiles |
📌 All lenses can be delivered uncoated or with AR coatings optimized for 8–12 µm or 3–5 µm.
Zinc Sulfide Refractive Index
The refractive index of ZnS varies with wavelength, averaging around 2.2 at 10.6 μm, making it ideal for:
- Collimation lenses in CO₂ laser systems
- Focusing optics in long-wave infrared (LWIR) detectors
- Beam shaping for thermal infrared imaging
Because of its high refractive index, AR coating is recommended to reduce surface reflection losses, especially in multispectral applications.
What Is Zinc Sulfide Used For?
Zinc Sulfide is used across a wide range of infrared and thermal optical applications, including:
- Thermal Imaging Cameras
- FLIR Systems
- Night Vision Equipment
- Infrared Targeting Systems
- Gas Detection Sensors
- CO₂ Laser Optics
- Defense & Aerospace Imaging
Is Zinc Sulfide Dangerous?
In solid optical form, Zinc Sulfide is not considered hazardous. However, like many fine powders and chemical compounds, inhalation of ZnS dust during polishing or grinding should be avoided and handled with proper ventilation and PPE.
✅ Non-toxic in lens form
✅ Safe to handle and install in optical systems
Zinc Sulfide Lens Applications at Bote Optical
Our custom ZnS lenses are used in:
- Infrared surveillance systems
- Uncooled thermal cameras
- Environmental gas detection
- Infrared microscopy
As a manufacturer, Bote Optical offers both standard and custom ZnS lenses with fast global delivery. We support small batches for R&D and large-scale OEM production.
FAQs
Q1: What’s the difference between ZnS and ZnSe lenses?
A: ZnSe lenses offer better transmission in the visible range, while ZnS lenses (especially Multispectral ZnS) provide higher durability and are preferred in rugged IR environments.
Q2: Can Zinc Sulfide be used for laser cutting systems?
A: Yes, ZnS lenses are compatible with CO₂ lasers and are commonly used in cutting, marking, and engraving applications.
Q3: How do I clean a Zinc Sulfide lens?
A: Use optical-grade isopropyl alcohol and lint-free wipes. Avoid harsh chemicals that may damage AR coatings.
Q4: Do you offer ZnS windows or domes in addition to lenses?
A: Yes, we offer ZnS windows, domes, and prisms. Custom geometries are welcome.
Why Choose Bote Optical?
- ✅ Precision machining of ZnS lenses in-house
- ✅ Singapore-based export & support
- ✅ Custom AR coatings (8–12 µm, 3–5 µm)
- ✅ Rapid prototyping + volume production
- ✅ ISO-compliant quality inspection and reporting
📌 Every ZnS optic is inspected for surface quality, transmittance, and dimensional tolerance before shipment.
- Inspection Equipment List and Metrology of Bote Optics
- Introduction of BOTE Key Equipment
- Catalog of Precision Optics
- Catalog of Imaging Optics
- ISO9001-2015 Certified
Contact Us for Custom Zinc Sulfide Lenses
Need a specialized Zinc Sulfide lens for your IR system? Contact our expert team for a free technical consultation.
📧 Email: [email protected]
🌐 Website: www.bote.com.sg
📍 Singapore HQ with China manufacturing base