Achromatic Waveplate

Achromatic Waveplate


Achromatic waveplates are similar to zero-order except that the two plates are made from different material, such as crystal quartz and magnesium fluoride. Since the dispersion of the birefringence can be difference for the two material, it is possible to specify the retardation value at a wavelength range. Hence the retardation of the resulting waveplate can be made to low sensitivity to wavelength change. Based on the contact methods of the two plates, achromatic waveplates are classified into two types: air-spaced and cemented.

  Standard Wavelength

VIS 465nm-610nm
NIR 700nm-1000nm
IR 1200nm-1650nm

Capability

Attribute  Commercial Quality  Precision Quality 
Material Crystal Quartz/MgF2
Dimension Tolerance +0/-0.1mm ±0.02mm
Wavefront Distortion Lambda/8@632.8nm Lambda/20@632.8nm
Retardation Tolerance@23°C Lambda/240@632.8nm Lambda/500@632.8nm
Wavelength Range 240-2100nm 240-2100nm
Parallelism <3 arc seconds <1 arc second
Surface Quality S/D 20-10 S/D 10-5
AR/AR Coating R<0.2%@ central wavelength R<0.1%@ central wavelength