Optical filters

n

Hi Syd, As with electronic filters it's all about what specs you need. (how sharp are the corners, how much transmission, price...) If you just want to pass a single wavelength (sorta +/- a few nm) then an interference filter may be your best bet.

There are then hot and cold mirrors, that pass or reflect different wavelengths (I've never used one.) Most of the colored glass filters tend to be low pass (called long pass by optics guys) They pass all wavelengths longer than some cut-off. You could start by searching through Thorlabs.

(They seem to call interference filters bandpass filters now... which is fine.)

George H.

I suspect you will probably find something like what you want at Edmund Scientific Optics under bandpass filters or you might get away with a Schott colloidally coloured glass eg GG435 - never tried any of the blue end long pass filters so no idea if they will do what you want.

Colloidal glass transition from 85% tranmission to 0.007% 40nm Bandpass anything is possible for a price but 5nm fwhm is a stock item.

A relatively cheap H-beta line (486nm) filter sold to amateur astronomers might be detuned slightly to do what you want.

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Regards,
Martin Brown

If you don't find anything you need at Edmund (I was going to suggest that, until Martin beat me to it), send me an email off list.

I have some former coworkers who might reply to my emails, and almost certainly know who to send you to if they're not in a position to sell you some custom-made stuff themselves.

Getting filter material in a rod format may not match what's out there -- if you end up with a dielectric filter those are made by depositing layers of clear material with different indexes of refraction at carefully controlled thicknesses (usually 1/4-wavelength). So it's more reasonable to expect a puck (however small) than a rod.

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

Omega Optical Inc.

Makes low cost custom dielectric optical filters. I've had good luck with them on optical projects, and they sell overstock as seller bjomejag on Ebay.

If any one can put a coating on a rod end, its Omega.

This is not a endorsement by my employer.

Steve

Somehow I find that remark quite funny.

I have been wondering why all the sunglass makers stopped offering "green fly eye" coatings. They must be a lot more expensive to do.

I see red, blue, orange... everything but green.

What, in the sense of "doc, I just asked her if she could coat my rod end until all I could see is blue, and the next thing I knew I was waking up here!" sort of funny?

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

I think I saw John Lennon once wearing the item we currently seek.

I want to meet this Omega chick. She sounds talented. :-) I wonder if she does engineering samples...

More likely that they found that green sunglasses didn't sell.

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Regards,
Martin Brown

She's the living end.

More likely that they found that ANY mirrored glasses sell well, and that MOST of YOU idiots will buy them, and NOW we are back to green fly eye is no more because it costs far more to apply. It has nothing to do with sales popularity, because they are popular. It is simply that all of the pants down past the asscrack idiots out there these days are so stupid, they will buy anything the next rap retard wears,so ANY mirror is fine. Which puts us back to the reason they are not being made right along with all the other mirror coatings is COST.

If they were made, they would sell just fine.

How can your common sense be that far off?

No... She's what makes my end live!

While your wavelength is a bit too short for typical CWDM applications, you might check, if the CWDM people might have something useful for you.

You should call some places. I'm thinking just a filter. Edmund, or edmunds anchor company. Coatings I don't know.

Greg

Edmund Scientific,or Edmund Optics.

I think they do custom tasks. Mirrors, flats, etc, so coatings and special "post style" filters would seem producible. Maybe even an off the shelf item already in the channel.

1mm diameter is pretty small. You cannot get this filter into the system at a location other than in the fiber segment? You know, a place where the thickness (length)can be less and the diameter more.

Still 1mm seems pretty small for a face. Will it be the final element? As in at the head of the snake?

Anyway, seems like it will get hot if power is involved. With no data about why it needs to be trimmed to such a tight spectral window either.

There are mirrors that act as filters as they reflect specific band windows. That would involve far less attenuation too.

I doubt anyone has a rod. Check out.

The shortpass filter is probably the cheaper solution.

Thanks everyone for your suggestions, that's given me a good start and a lot to investigate.

Cheers

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Syd