Polymer waveguides under ion implantation: optical and chemical aspects

The effects of ion implantation on the linear and nonlinear optical properties of polymer thin films are studied. In the first step, good quality planar waveguides were made in a well known photoconducting polymer, polyvinylcarbazole (PVK), which has no intrinsic nonlinear optical properties. The polymer is deposited by spin-coating onto a BK7 glass substrate. A diffraction grating, etched on the substrate surface, acts as an input coupler for the waveguide. We present our results from the study of these polymer waveguides, following exposure to an energetic ion beam. The grating coupler method was used to characterize the linear and nonlinear optical properties of the waveguides before and after ion implantation. Due to the conjugated chains created by the implantation, we expect χ(3) type nonlinear properties and more specifically, an electronic nonlinear refractive index. The implanted polymer films are characterized by infrared and UV/visible spectroscopy to study structural modifications. The new structures created and the significant damage caused by the implantation are discussed