Calcite(CaCO₃) is the only natural mineral among our crystals. Because of its high birefringence, wide spectral transmission and availability in large size, Calcite is a traditional and still ideal material for visible and near IR polarizing applications. 

Transparency Range: 300-3000nm

Density:2.71 gram/cm³

Mohshardness: 2

Low susceptibility to moisture

Thermal Expansion Coef.: //c 26.31, ⊥c 5.44 (x10^-6/K)

Refractive Indices, Birefringence(Δn=n_o-n_e)& Walk-off Angle @ 45^o(ρ):
@630nm n_e=1.4852, n_o=1.6557, Δn=0.1705, ρ=6.2°

@1300nm n_e=1.4885, n_o=1.6629, Δn=0.1744, ρ=6.32°

Sellmeier Equation(λ in μm):
n_o²=2.69705+0.0192064/(λ²-0.01820)-0.0151624λ²
n_e²=2.18438+0.0087309/(λ²-0.01018)-0.0024411λ²

 

Features and Standard Specifications from LNG Optics:

Orientation accuracy: ±0.5^o

Dimension Tolerance: ±0.2mm

Surface quality: 20/10 Scratch/Dig

Flatness: λ/4 @ 633nm

Transmitted Wavefront Distortion: λ/4 @ 633nm

Parallelism: 30 arc seconds

Wedged angles accuracy: 3 arc minutes

Perpendicularity: 5 arc minutes

AR Coatings: single band, broadband