BK7 CaF2 Znse Optical Window Lens for UV and IR Optical Systems

1. Material Composition & Core Function:

• Hybrid Material Solution: Combines three distinct optical materials (BK7 glass, Calcium Fluoride crystal, Zinc Selenide) into a single protective window/lens element.

• Primary Function: Acts as a robust environmental barrier and broadband transmitter for optical systems operating across ultraviolet (UV), visible (VIS), and infrared (IR) spectra.

2. Key Material Properties & Spectral Strengths:

• BK7 Glass (Borosilicate):

  • Transmission: Excellent in Visible (VIS) spectrum.

  • Properties: High mechanical durability, good chemical resistance, cost-effective. Provides structural integrity.

• CaF2 (Calcium Fluoride):

  • Transmission: Exceptional deep UV transmission (down to ~190nm), good in VIS and Near-IR (NIR). Resists radiation darkening.

  • Properties: Low refractive index dispersion, low thermal expansion, high laser damage threshold. Relatively soft.

• ZnSe (Zinc Selenide):

  • Transmission: Outstanding broadband transmission from NIR through Far-IR/LWIR (up to ~20µm).

  • Properties: Essential for thermal IR & CO₂ lasers (10.6µm), good thermal shock resistance. Moderately soft, sensitive to moisture/abrasion (often requires coatings).

3. Combined Critical Properties:

• Ultra-Broadband Transmission: Seamlessly covers UV (via CaF2), VIS (via BK7/CaF2), and IR (via ZnSe/CaF2) wavelengths in one component.

• Robust Environmental Barrier: Protects sensitive internal optics (sensors, lasers, detectors) from dust, moisture, contaminants, and physical damage.

• Optical Integrity: Maintains low wavefront distortion for accurate light transmission.

• Durability: Leverages BK7's hardness while benefiting from CaF2/ZnSe's thermal and laser handling capabilities.

4. Primary Function:

• To transmit light efficiently across the UV-VIS-IR spectrum while hermetically sealing and safeguarding the internal components of sophisticated optical instruments operating in these demanding wavelength ranges.

5. Key Applications (UV & IR Systems):

• Multispectral & Hyperspectral Imaging Systems: Covering UV-VIS-NIR-SWIR-MWIR-LWIR ranges.

• High-Power Laser Systems: Protective windows for UV excimer lasers, frequency-multiplied Nd:YAG lasers, and especially CO₂ lasers (10.6µm) where ZnSe excels.

• Thermal Imaging (IR Cameras): Windows for SWIR, MWIR, and LWIR cameras (e.g., FLIR systems).

• Broadband Spectroscopy: FTIR, UV-VIS-NIR spectrometers requiring wide spectral access.

• Defense & Aerospace: Domes and windows for missile seekers, surveillance systems, targeting pods.

• Scientific & Research Instruments: Equipment requiring performance across extreme UV and IR wavelengths.