Photoinduced Refractive Index Increase in Poly(methylmethacrylate) and Its Applications

Ultraviolet laser radiation at 0.325μ m has been found to produce refractive index increases of up to 3×10−3 in poly(methylmethacrylate) and to resolve at least 5000 lines/mm. The index change is tentatively attributed to localized density increases arising from photoinduced cross linking. Applications to optical waveguides and thick dielectric holograms and gratings are described.