Optics > Detection

For night-vision devices, for instance, windows made of transparent Al2O3 in the form of monocrystalline leucosapphire are used as this material is permeable to wavelengths in the range from 250 – 5 000 nm. As, on the basis of the MoMn process, the leucosapphire can be soldered and firmly bonded high-vacuum-tight with metallic partners like, for example, Ni42 (1.3917) or NiCo2918 (1.3981), welded joints with other equipment components can be realized. Soldered component diameters of 50 mm and larger can be realized without any problem with a suitable cut of the sapphire disc.

Some technical properties of the leucosapphire can be summarized as benchmarks with reference to standard conditions, the data areas specified in the following predominantly indicating the anisotropic character of its crystal structure:

  • Optical transmission range: 250 – 5 000 nm
  • Refractive index: (nw) = 1.767 – 1.772, (ne) = 1.759 – 1.763
  • Birefringence: (δ) = 0.008 – 0.009
  • Specific electrical resistance: 1014 Ohm*cm
  • Dielectric constant: 8.6 – 11
  • Density: 3.99 g/cm³
  • High resistance to wear and scratches
  • Surface quality in line with MIL standards
  • Tensile strength at room temperature: 185 MPa
  • Compressive strength at room temperature: 2 000 MPa
  • Modulus of elasticity: 400 GPa
  • High chemical corrosion resistance
  • High thermal and thermomechanical strength
  • Thermal expansion: 5.5 – 6.5 ppm/K
  • Thermal conductivity: 35 – 40 W/m/K

Products

Products for the application
Detection

Night vision equipment

      IR-transparent ceramics

Suppliers