Zinc Selenide (ZnSe) Windows

Zinc selenide (ZnSe) window is an important infrared optical material widely used in multiple fields.

Basic characteristics
Transmittance range: 0.5-22 microns, covering visible light (yellow/red), near-infrared to far-infrared bands, especially excellent performance in 8-12 μ m (atmospheric window).
Refractive index: about 2.4 (@ 10 μ m), requiring anti reflective coating to reduce reflection loss.
Physical properties: Melting point of about 1520 ° C, moderate hardness (Mohs hardness of about 3.5), better than calcium fluoride (CaF ₂) but lower than silicon (Si) and (Ge).
Chemical stability: resistant to moisture and general chemical corrosion, but avoid strong acid/alkali environments.

Core applications
High power laser systems, such as lenses and windows of CO ₂ lasers (10.6 μ m), reduce thermal lens effects due to low absorption.
Thermal imaging and infrared detection: used in FLIR systems and night vision devices.
Spectral analysis: Fourier transform infrared spectroscopy (FTIR), gas detection.
Medicine and Industry: Laser Surgical Instruments, Material Processing (Cutting/Welding).

Advantages and limitations
advantage:
High transmittance (>70% @ 10.6 μ m), low absorption loss.
Good chemical stability, suitable for humid environments.
Easy to process into complex shapes, supports coating optimization performance.
Disadvantages:
High cost: More expensive than silicon and , especially for large-sized or high-precision requirements.
Low mechanical strength: easy to scratch, requiring protective coating or careful handling.
Visible light transmission band color: appears orange yellow and may affect multispectral applications.

Usage and maintenance suggestions
Avoid mechanical impact: Use soft pads during installation and regularly clean the surface.
Coating protection: Choose wear-resistant or anti reflective coatings according to the application environment.
Temperature control: Rapid temperature changes may cause cracking, and slow heating/cooling is required.

Zinc selenide window is a key component of infrared optical systems, suitable for high-precision laser and imaging fields. When selecting, it is necessary to weigh the transparency requirements, mechanical strength, and cost, and pay attention to environmental adaptability. In scenarios where both visible light and infrared transmission are required, ZnSe is superior to Ge, but if mechanical durability is pursued, ZnS or composite material solutions can be considered.