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Knight Optical supplies quality achromatic retarders made from quality crystal quartz and magnesium fluoride, then mounted with an air gap in durable blackened aluminium rings for ease of integration and handling. Combined with high quality broadband AR coatings on both surfaces enables consistant phase retardation over the entire wavelength.

Key applications include:

  • Tunable lasers
  • Multiple laser line systems

Wave plates can be used to rotate the direction of polarisation (λ/2 type) or convert linear to circular polarisation (λ/4 type). The effect of the wave plate is dependent on the retardation. Unlike low or zero order retarders, achromatic retarders are designed to offer a consistant phase retardation over a broad wavelength range.

Our achromatic retarders are available designed for use between 450-1650nm and are available to purchase directly from this page. Bespoke wavelengths, sizes and mounts are available through Knight Optical’s extensive custom optical service. Contact our technical sales team for more information.

Mount diameter:
Quartz Thickness:
Retardation Tolerance:
Laser Damage Threshold:
Crystal quartz, MgF2
25.4mm +0/-0.2
AR Ravg < 0.8%
0.15 - 0.35mm
< λ/100
>3J/cm2 , 10 nsec, 1064 nm typical

Alternative wavelengths and sizes available
Custom mounts manufactured to fit your applications
Can be purchased as a set supplied in a wooden box for research and laboratory use

8 Items

Name Wavelength (nm) Retardance Wavefront Distortion @ 633nm Material Price Buy
RAC2540 450-680 1/4 wave 1/4 wave Quartz/MgF2
RAC2520 450-680 1/2 wave 1/4 wave Quartz/MgF2
RAC2541 700-1000 1/4 wave 1/4 wave Quartz/MgF2
RAC2521 700-1000 1/2 wave 1/4 wave Quartz/MgF2
RAC2542 950-1300 1/4 wave 1/4 wave Quartz/MgF2
RAC2522 950-1300 1/2 wave 1/4 wave Quartz/MgF2
RAC2543 1200-1650 1/4 wave 1/4 wave Quartz/MgF2
RAC2523 1200-1650 1/2 wave 1/4 wave Quartz/MgF2

8 Items


Achromatic Retarders

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