Spectroscopic study of surface effects in polymer waveguides generated by ionizing radiation related to guiding properties

Abstract

Samples of PMMA (Poly-(Methyl-Meth-Acrylate)) have been modified by ionizing radiation (especially UV-radiation) in order to generate regions of increased refractive index for the use as optical waveguides in a surface layer. To get a befler understanding of the formation of these guides the chemical processes which are responsible for the increase of the refractive index were studied using different spectroscopic methods. It is shown that the tickness as well as the refractive index profile of the layer at the surface depends on the irradiation dose. In this paper also the guiding properties of the waveguides in dependence of these parameters are discussed. The waveguiding structures were used to build optical polarizers simply by varying the exposure time. The spectral absorption behavior of different strip waveguides for different exposure doses were studied.

Selective Surface Smoothening of Polymer Microlenses by Depth Confined Softening

“…The associated high penetration depths do not allow for the required dose confinement. UV exposure to PMMA film is studied for fabricating optical waveguides as it results in increase in the refractive index . EUV (λ = 13.5 nm) and vacuum UV (VUV, λ = 172 nm) are equally suited for a surface selective exposure having up to 400 nm depth where significant modification occurs.…”

Novel polymer waveguides consisting of an alicyclic methacrylate copolymer

“…[7][8][9][10][11][12] By deep-UV exposure the refractive index of the polymer could be altered. [13][14][15][16][17] By using lithographic techniques using standard photomasks (Cr on glass) a local and controllable increase of the refractive index in the exposed areas of the polymer surface could be achieved, generating the integrated-optical waveguiding structures. The technique presented here has several advantages with respect to other methods because only a single polymer layer is required, which serves as substrate and waveguide as well and no further etching, development step or filling with higher index polymer is required.…”