Quartz Crystal (SiO2) for infrared polarisers
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Quartz Crystal (SiO2) for infrared polarisers - 1

Crystal Quartz Polarizers for the Infra-Red Waveband ^^^-^^ Knight Optical can offer Crystal Quartz (Si02) Polarizers for Infra-red systems over the waveband of 0.2 to 2.3um. Crystal Quartz is a birefringent material that makes it useful for polarizers and waveplates. A typical arrangement for laser polarizers is in the Wollaston Prism is a polariser using Crystal Quartz. The Wollaston consists of two prisms that are cemented together and the two output rays, the s and p polarisation, are deviated nearly symmetrically within a degree or two. The deviation is about ±1° at 2.3um and increases as the wavelength is reduced, about ±3° at 200nm. The clear aperture is about 10mm in diameter with a wavefront distortion that is less than one quarter of a wave at 633nm. Wollaston Prisms' are used in spectrometers and other optical arrangements to separate, or combine, the s and p polarizations. The The Rochon is another configuration that uses crystal quartz for depolarizers as in the figure below. The Rochon operates by having the ordinary and extraordinary rays propagate co-linearly along the optic axis of the first prism. Upon entering the second prism the ordinary ray 'sees' the same refractive index and thus continues undeviated at this interface. However, the extraordinary beam now 'sees' a lower refractive index and is thus refracted at the The angle of refraction is further increased at the exit surface. It is possible to have tune the separation angle at a specific wavelength within the limits for crystal extinction ratio is 100,000:1 as with the Wollaston prism. All content on this drawing is protected under the Copyright, Designs and patents act 1988 and the Copyright © is owned by Knight Optical (UK) Limited 2011. All rights are reserved. Reproduction of any content, by any means, without the express permission of the owner is prohibited by law. The Knight Optical name and/or mark and KO KNIGHT OPTICALLOGO are the trademarks of Knight Optical (UK) limited. KNIGHT OPTICAL Knight Optical (UK) Limited © Whilst every effort has been made to verify the information and data, Knight Optical (UK) Limited can take no responsibility for its accuracy The KNIGHT OPTICAL name and/or mark and KO KNIGHT OPTICAL LOGO are the trade marks of Knight Optical (UK) Limited

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Quartz Crystal (SiO2) for infrared polarisers - 2

Crystal Quartz Polarizers for the Infra-Red Crystal Quartz is used to make Depolarizer that consist of two wedge plates where one is twice the thickness of the other, and the optic axes of the plates lying in the plane of the plates with a mutual 45° angle between them. The result is a variable retardation plate over the aperture, which produces depolarization for all wavelengths. Anti-reflection coatings are required on the entrance and exit plates to minimize beam loss. Crystal Quartz is an excellent material for quarter and half wave plates within wavelength ranges. It is available for...

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