Achromatic Retarders The Fresnel Rhomb is unique among retarders in giving a fractional-wave retardation nearly independent of wavelength, the variation due to change of index with wavelength being less than ±1% through the visible (450-700nm) and within ±4% throughout the range of transparency (350-2500nm). The variation with angle is also small (less than ±6% over ±5%) and spurious stress birefringence is reduced by use of a fine-annealed grade of glass. The single (quarter-wave) rhomb gives an output parallel to the input but laterally displaced. The double (half-wave) rhomb has input and output coaxial.
Knight Optical > Retarders > Achromatic retarders Only UK and EU customers are charged VAT at 17.5%, customers outside the EU and EU customers based outside the UK who have a valid EU VAT number will not be charged VAT Bulk Discounts! Where (B) appears next to a price below, bulk prices are available, click the (B) button to view! PDF Part No. Material Length (mm) Type Price Qty Buy RYK3116 BK7 31.3 Single 1/4 wave £61.20 RQK6316 BK7 62.6 Double 1/2 wave £128.20 Knight Optical > Retarders > Achromatic retarders
Specification   Material: BK7 Material Data: (see materials section) Aperture: 16 x 16 mm Lateral Offset: (single rhomb) 21.6 mm Angles: 55°20’ ± 5’
Specific requirements We can manufacture Achromatic retarders to any size at short notice, so if your requirements are not listed please contact us by telephone / fax or email: stockrequirement@knightoptical.co.uk