Calcite Crystal

Crystal Structure

Crystalline rhombihedral

Density

2.7 g/cm³

Mohs Hardness

3

Hygroscopic Susceptibility

Low

Transparency Range

350nm ~ 2300nm

Thermal Expansion Coefficient

aa=24.39x10^-6/K

ac=5.68x10^-6/K

Crystal Class

Negative uniaxial with no=na=nb, ne=nc

Refractive Index

Birefringence (Δn=ne-no)

Walk-Off Angle at 45 deg(ρ)

no=1.6557, ne=1.4852, Δn = -0.1705, ρ=6.32 @633nm

no=1.6381, ne=1.4783, Δn = -0.1598, ρ=6.20 @1300nm

Sellmeier Equations ( in um)

no²=2.69705+0.0192064/( λ²-0.01820)-0.0151624λ²
ne²=2.18438+0.0087309/( λ²-0.01018)-0.0024411λ²

Dimension Tolerance

±0.1

Optical Axis Orientation

±0.5deg

Wavefront Distortion

<λ/2 at 633nm

Surface Flatness

<λ/4 at 633 nm

Surface Quality

20/10 Scratch and Dig

Parallelism

<15 arc seconds

Perpendicularity

<10 arc minutes

Clear Aperture

>Central 90%

AR-Coating

R<0.25%@ 1550nm±40 nm