Need a photosensitive polymer with n=1.6, minimal absorption at 780nm and 1550nm

Aug 02, 2004 1 Replies

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Nathaniel Burt 21 years ago

I'm having trouble finding polymers that meet the following specs:

1) refractive index between 1.5 and 1.7 (ideally 1.6)
2) photosensitive
3) very low absorption at ~775nm and ~1550nm

I want to have a 2-5um-thick layer after spinning.

So far, the only promising candidate is 4000 series Cyclotene (a.k.a. BCB, by Dow), but it's only available in large quantities. Sigma-Aldrich has a wide variety of high-index "waveguide materials," but there isn't any absorption data.

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Does anyone know of any relatively cheap polymers that fit the bill? Thanks.

Nathaniel

4000 series Cyclotene info:

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John Spevacek 21 years ago

The Polymer Handbook, most likely available at any nearby technical university, has a 4+ page list of polymer and their refractive indices, sort in order of increasing index. Polystyrene 1.592, hard rubber (32% S) 1.6, PVDC 1.60-1.63, polysulfides 1.6-1.7, polysulfone

1.633. There are others on the list that probably match up with the Aldrich list, but the ones I listed some of the big thermoplastics.

Photosensitive in what way? To which wavelengths?

How low is "low absorption"? The C-H stretch has a 4th overtone in the

690-780 nm range, but being a 4th overtone, it is pretty weak, hopefully weak enough or you will be having problems from any organic material.

John

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