Re: Modelling Interference Filter Performance Using Zemax and Encrypted Coatings Files

On Mar 21, 11:46 am, "Jarvis" <john.jarvis @ yahoo.co.uk> wrote:
I'm working on a project that uses narrow bandpass interference filters
(near 1.5 um) in a non-normal incidence configuration.  Additionally, the
light incident on the filters can have varying amounts of non-random
polarization.  This variation in incident polarization will have an effect
on the amounts of "s" and "p" polarization that the filter experiences.  As
a result, the amount of transmitted light will vary because of the differing
filter transmission characteristics for "s" and "p" polarized light.

I'm using Zemax as a design tool and trying to estimate/calculate the
effects polarization variation on system performance.  Zemax has the
capability of importing coatings files from thin film design programs like
Essential McLeod in an encrypted format (i.e. files have ZEC extension) that
protect the coater from having his intellectual property being reversed
engineered.  Alternately, I could use a reasonable description of filter
characteristics for "s" and "p" polarization as a function of incidence
angle.

So, it seems like all the engineering design tools are in place.  However, I
seem to be having trouble finding a filter/coating vendor willing to supply
these encrypted coatings files.  Nor can I find one who is willing to supply
representative "s" and "p" transmission vs. angle characteristics.  I'm
certainly willing to purchase custom designed filters but not without a
knowledge of these transmission characteristics.

Has anyone been through this before with any success?  Can you recommend
capable vendors?

Sincerely,

John

I wouldn't expect any vendor to let you have coating files, encrypted
or not. Encryption is usually very easy to break. However, I would
expect them to supply you with data for s and p reflectivity of their
present filters. After all, when they deliver a filter measured data
is usually included. (If you need "unusual data" you could offer to
pay for it.)

Have you tried Omega Optical, Chroma Technology, Lambda Research,
Optisigma or Barr?
.

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