Consisted of two different substrate materials: quartz and
  magnesium fluoride with the optical axes orthogonally
  oriented. 
Air-spaced design with high transparency.
Very large wavelength bandwidths 200-1000nm.
Suitable for use with broadband dye and tunable
  femtosecond lasers.
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Achromatic Waveplate Specifications

Dimensions Tolerance: +/- 0.1 mm
Wavefront Distortion: < λ/8 @632.8nm
Retardation Tolerance: < λ/100
Surface Quality: 20-10 scratch and dig
Coating: AR coating with R < 0.2% at the center wavelength
Holder: Anodized aluminum holder

Structure and
the optical axis