ZnSe Bi-Concave Lenses
ZnSe Bi-Concave Lenses with negative focal length for IR beam expansion. Diameter 1-500mm, focal length 4.5-1000mm. IR2 AR coating available.
Product Overview
Overview
ZnSe Bi-Concave Lenses have a negative focal length and can diverge a parallel beam to the virtual focus, making them an excellent choice for diverging convergent beams and for relay imaging systems. These lenses are based on CVD Zinc Selenide, which offers low absorption, thermal shock resistance, and wide transmission band (0.6–16 µm).
ZnSe is often used in optical systems that combine CO₂ lasers (operating at 10.6 µm) with helium-neon lasers for alignment, due to its low absorption in the red part of the visible spectrum.
Why This Material Matters
CVD Zinc Selenide (ZnSe) is selected for its low absorption and high infrared transmission, making it ideal for CO₂ laser optics and thermal imaging systems. The double-concave geometry provides negative focal length for beam expansion and divergence control.
Key Specifications
| Parameter | Value |
|---|---|
| Material | CVD Zinc Selenide (ZnSe) |
| Diameter Range | Ø1–Ø500 mm |
| Focal Length Range | 4.5–1000 mm (negative) |
| Wavelength Range | 0.6–16 µm (uncoated); 7–12 µm (IR2 AR coated) |
| Clear Aperture | >90% |
| Diameter Tolerance | +0.00/-0.1 mm |
| Thickness Tolerance | ±0.1 mm |
| Surface Irregularity | λ/4 @ 633 nm (λ/8 optional) |
| Centering Error | 3 arcmin |
| Focal Length Tolerance | ±2% |
| Chamfer | 0.2 mm × 45° |
Coating Options
Uncoated versions transmit from 0.6–16 µm. IR2 broadband anti-reflection coating is available with Ravg < 1.5% @ 8–12 µm for improved transmission in thermal imaging and CO₂ laser applications.
Typical Applications
- IR beam expansion and divergence control
- CO₂ laser beam delivery systems
- Thermal imaging optics
- Infrared relay imaging systems
- Optical test benches and alignment systems
- HeNe laser alignment in CO₂ laser systems
Safety Note
Zinc Selenide is a toxic material. Always wear gloves when handling ZnSe components and thoroughly clean hands after operation. Dispose of waste according to local regulations.
Engineering Notes
For custom production, specify focal length, diameter, center thickness, coating target, and beam diameter. Engineers should confirm wavelength, beam diameter, clear aperture, coating requirements, and mechanical envelope before final drawings are released.
Use the contact form or email sales@iroptical.com to request engineering review, coating options, or a quotation.
Technical Parameters
Detailed specifications are not available for this product yet. Please contact the team for application guidance.