Bi-Crystalline Achromatic Retarder

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Bi-Crystalline Achromatic Retarder

Meadowlark Optics is pleased to offer a selection of quarter- and half-wave achromatic retarders that span the UV, visible, near IR and IR portions of the spectrum. Two multi-order crystalline retarders, one made of crystalline quartz and the other magnesium fluoride, are combined in a subtractive mode to give an effective zero-order waveplate. By a careful choice of waveplate thicknesses, retardance dispersion is balanced to give a nearly constant retardance (in waves) over a broad range of wavelengths. The useable wavelength range is defined to give a retardance value within λ/100 of the nominal value. Custom designs with larger achromatic ranges or deeper UV wavelengths are available on request.
 
Bi-Crystalline Achromats are similar in achromatic performance to our polymer achromats in the visible, but they excel in the IR. They have higher power handling capability than our polymer achromats and can with stand higher storage temperatures. Their field of view is narrow compared to polymer achromats. Typically, they cannot be expected to meet their retardance accuracy for rays whose incidence angles exceed 1.5°. If you must have the performance of a Bi-Crystalline Achromat and a large field of view, call us. We have a proprietary design that can be your polarization solution.

  • High Damage Threshold
  • Volume Pricing
  • Superior IR performance

Specifications - Bi-Crystalline Achromatic Retarder
Retarder Material Quartz & Magnesium Fluoride
Retardance Accuracy λ/4 or λ/2
Temp. Coefficient of Retardance λ/500 per ˚C
Standard Wavelengths - Quarter Wave
Ultraviolet
Visible
Near Infrared
Infrared
395-465 nm
475-590 nm
600-900 nm
690-2050 nm
Standard Wavelengths - Half Wave
Ultraviolet
Visible
Near Infrared
Infrared
412-475 nm
500-650 nm
600-840 nm
1190-1660 nm
Transmitted Wavefront Distortion ≤ λ/4
Surface Quality (scratch-dig) 40-20
Beam Deviation ≤ 1 arc-min
Reflectance (per surface) ≤ 0.5% at normal incidence
Storage Temperature -40˚C to +75˚C
Threshold 2 J/cm2, 10 ns, 1064 nm
 

 

Ordering Information - Bi-Crystalline Achromatic Retarders
Mounted
Clear Aperture
in. [mm]
Diameter
in. [mm]
Part
Number
Half Wave
0.40
[10.2]
Ø1.00
[Ø25.4]
CHM-050
Quarter Wave
0.40
[10.2]
Ø1.00
[Ø25.4]
CQM-050
Unmounted
Clear Aperture
in. [mm]
Diameter
in. [mm]
Part
Number
Half Wave
0.40
[10.2]
Ø0.50
[Ø12.7]
CH-050
Quarter Wave
0.40
[10.2]
Ø0.50
[Ø12.7]
CQ-050
We offer standard Bi-Crystalline Achromatic Retarders to cover 4 regions of the spectrum: UV, VIS, NIR, IR
Please specify wavelength region when placing order.