GERMANIUM QUALITY SPECIFICATIONS FOR IR OPTICS

MECHANICAL PROPERTIES
Young Modulus : 103 GPa
Shear Modulus : 67.04 GPa
Bulk Modulus : 77.86 GPa
Rupture Modulus, at 25°C : ≥ 75 MPa
Knoop Hardness : 8.3 GPa
Mohs Hardness : 6.3
Poisson’s Ratio, between 148°C…102°C : 0.28
Density : 5.33 g/cm3

THERMAL PROPERTIES
Melting Point : 937°C
Max working temperature (with coating) : 90°C
(above 90°C, transmission decreases and goes
back to normal values when temperature
decreases)
Boiling Point : 2830°C
Specific Heat : 0.074 cal/(g·°C) a 0-100°C
Linear Thermal expansion coefficient, at 27°C : 6.1 x10-6 °C-1
Thermal Conductivity, at 27°C : 60 W/(m·°C)

ELECTRICAL PROPERTIES
Dielectric constant : 16
Resistivity, at 20°C : 5-40 ohm-cm
Conductivity type : N-type

OPTICAL PROPERTIES
Trasmssion Range : 1.8...23μm
Reafractive Index : 4.0026 at 11μm
Variation of refractive index with temperature : 0.0004 C-1 at 20°C…125°C