Crystals Land

  Calcite (CaCO₃)

Calcite is a natural crystal that has high birefringence and wide spectral transmission and available in reasonably sized rhombs. It is a negative uniaxial crystals and commonly used as visible and near IR polarizer.

Physical and Optical Properties:

Transparency range	350~2300nm
Structure	rhombihedral
Density	2.7 g/cm3
Hygroscopic susceptibility	Low susceptibility to moisture
Mohs Hardness	3
Thermal expansion coefficient	αa=24.39x10-6/k; αc=5.68x10-6/k
Refractive index, birefringence(Δ=ne-no) and walk-off angle at 45o(ρ)	no =1.6557, ne=1.4852, Δn=-0.1705, ρ= 6.20o@ 630nm
	no =1.6629, ne =1.4885, Δn=-0.1705, ρ= 6.20o@ 1300nm
Sellmeier equation (l in mm)	no2=2.69705+0.0192064/(l2-0.01820)-0.0151624l2 ne2=2.18438+0.0087309/(l2-0.01018)-0.0024411l2

Specifications:

Diameter	max 30~40mm
Length	max 25~35mm
S/D	20/10
Beam deviation	< 3 arc min
Optical axis orientation	+/-0.5º
Flatness	l/4 @632.8nm
Transmission wavefront distortion	<l/2 @632.8nm
Coating	Upon request