Exploring the High Price of Wollaston Prisms: Factors and Alternatives

[Flavio]

I would like to buy a calcite Wollaston prism, but they are priced €450-700 for 10x10mm to 14x14mm prisms (plus €150 for "broadband antireflection coating") which means way beyond my budget. I was wondering why are these objects that expensive? I have asked the same question to two different manufacturers; one did not reply, the second told be "because of raw materials".
The best I have found over the Internet is a sentence in this paper http://authors.library.caltech.edu/6948/1/SANrsi05.pdf which is "Wollaston prisms are expensive due to the large optical quality crystals required for their fabrication."

Do you know more details to explain the high price?
Do you have any idea on how I could replace a Wollaston prism with something cheaper (and which accomplishes the same task)?

Thank you

 

[xts]

Does £26.00 make it affordable?
Google for "polarisation beam splitters - cheap!".
You just looked for quotes for too proffessional devices ...

 

[Flavio]

Thank you xts, £26 would be ok but I am specifically looking for Wollaston-like prisms. My problem is that commercially-cheap polarization beam splitters work by internal reflection, therefore the 2 outgoing rays exit from 2 different faces of the prism. What I need instead, is the 2 divergent rays exit from the same face.
To make my problem more clear, you may look at 2 different representations here
http://en.wikipedia.org/wiki/Glan–Taylor_prism
http://en.wikipedia.org/wiki/Wollaston_prism

I have found a potentially interesting article here http://www.opticsinfobase.org/abstract.cfm?uri=ao-47-3-328 where they use "a polycarbonate prism under mechanical loading", but unfortunately it is not free and I do not have access to it.

Thank you again

 

[Claude Bile]

The high price comes from cutting, polishing and assembling crystals to the required specifications.

Why exactly do you need both beams to exit the same facet? If you give us more detail, perhaps we can come up with a workaround?

Claude.

 

[Andy Resnick]

Do you know more details to explain the high price?
Do you have any idea on how I could replace a Wollaston prism with something cheaper (and which accomplishes the same task)?

Thank you

The crystals are dug out of the ground, and in order to get high performance, the crystals have to have very few defects:

"Defects in bulk calcite are characterized by bubbles (presence of randomly scattered bubbles vary from relatively large to small sizes and fine bubble lines), striae (streaks of sudden variation of refractive index which can be detected interferometrically ), optical inhomogeneity (gradual variation of refractive index in bulk material ) and stress birefringence (variation of birefringence in bulk material due to defective growth of the crystal ). These defects cause degradation of polarization and transmission loss due to scattering and absorption." (from Karl Lambrecht's site, see below)

Plus, as Claude mentioned, the manufacturing steps are not inexpensive, either.

Karl Lambrecht (http://www.klccgo.com/) lists different grades, there may be something in your price range.

But in any case, as Claude asked- why do you need both beams to exit the same face? There are Rochon prisms that may be less expensive. What other specifications do you require- power levels, extinction ratios, beam deviations, acceptance angles, etc.

 

[Charles_Chen]

Hi guys, we have developed 20x20x20mm un-mounted Wollaston prisms with calcite.
We are a Singapore company, if any interest, pls email me:
charles.chen@photonik.com.sg