Foster Polarizers

The p-polarized ray passes undisplaced. The s-polarized ray is reflected and is transmitted through a hole in the wall of the enclosure. A modification involves mirror coating this top surface to reflect the s-polarized beam down at 90° to the transmitted beam. Only the transmitted ray has high polarization purity. Cemented: low power handling.

Description

The Foster polarizer is made of two calcite prisms cemented together. The output beams separate at an angle of 45°.

Although both beams are available for use, only the undisplaced beam is of the exceptionally high polarization purity generally associated with crystal polarizers. The 45° reflected beam has a much lower degree of polarization.

Specifications

As with all of our optics, we will gladly provide these items custom designed to your particular requirements. As an alternative, we offer a selection of standard items as specified below.

Standard products:

Order No.	L/A	Extinction Ratio	Angular Field (°)	CA phi a (mm)	O.D. phi d (mm)	L ± 0.1 (mm)
50.230.00110	2.4	<5x10-5	>15	6.0	50.8	33.0
50.230.00111	2.4	<5x10-5	>15	8.0	50.8	33.0
50.230.00112	2.4	<5x10-5	>15	10.0	50.8	33.0
50.230.00113	2.4	<5x10-5	>15	12.7	50.8	33.0
50.230.00114	2.4	<5x10-5	>15	15.0	50.8	38.0

You might also be interested in:

Glan Thompson Polarizer

Quality Assurance

We take quality control very seriously: we rely on accurate, widely recognized measurement systems for testing our optics. The following table indicates the accuracy of measurement for the most relevant parameters.

Surface figure: λ/20
Angle: 0,5 arcsec
Radius: 0,01%
Focal length: 0,03%-0,3%
Centration: +/-0,2µm or +/-2 arcsec
Wavelength: +/-0,3nm (190-1100nm)