CaF2 (Calcium Fluoride) Double Concave Lenses are high-precision optical components manufactured from high-purity calcium fluoride single crystals. Featuring two concave surfaces, these negative focal length lenses are designed for beam expansion, image projection, and optical system miniaturization, offering exceptionally high transmission from the ultraviolet (UV) through the visible and into the infrared (IR) spectrum with minimal chromatic aberration.

Technical Applications & Industrial Use Cases

Due to their wide transmission range, low refractive index, and high laser damage threshold, CaF2 double concave lenses are widely deployed across demanding high-tech sectors:

  • Laser Beam Expansion: Act as divergence elements in laser beam expanders and spatial filtering setups across UV, visible, and IR wavelengths.
  • Thermal Imaging & Spectroscopy: Utilized in multi-spectral optical assemblies, FTIR spectrometers, and thermal imaging systems operating in the 3 to 5 micrometer infrared band.
  • UV & Excimer Laser Systems: Deployed in semiconductor lithography, laser material processing, and scientific research requiring high resistance to laser-induced damage.

Key Specifications & Performance Advantages

  • Material: High-purity Calcium Fluoride (CaF2) single crystal optimized for broad-band transmission.
  • Design Wavelength: Engineered for precision performance with strict focal length tolerance (EFL $\pm 1\%$).
  • Surface Quality: High-precision 60-40 scratch-dig with tight centration tolerance (< 3 arcmin) and protective chamfers ($0.2\text{ mm} \times 45^{\circ}$).
  • Coating Options: Available uncoated or featuring specialized low-absorption infrared anti-reflective (IR1) coatings (average reflectance < 1.5% across 3 to 5 micrometers) to maximize throughput.

Download Datasheet of CaF2 Double Concave Lens