[gohteikbeng]

How high is the high refractive index can go for epoxy?
Is hybrid silicone epoxy workable
Another way is by incorporate nanoparticle but when I disperse into epoxy, it is cloudy! anyway to make it clear?

[marquis]

Had a similar discussion with a LIM silicone rubber salesman a while ago.  The silicone rubber he sold was clear, but he claimed it was a highly filled compound.
When I pressed for details, he said that as long as the refractive index of the particles matches the refractive index of the rubber, it could be made clear.

That is not definitive.  Salesmen will sometimes mislead when it comes to proprietary information.  But it is something you could investigate.