Photoprogrammable molecular hybrid materials for write-as-needed optical devices

Abstract

The application of photosensitive materials to provide immediately configurable optical device functionality in integrated photonic systems has motivated an examination of the unique materials requirements associated with this alternative operational mode. In this case, a reliable photoinduced index change is needed when photopatterning under non-laboratory conditions utilizing compact, integrable optical sources. Molecular hybrid thin films, based on inorganic, Group IVA linear-chain polymers, are investigated in terms of excitation (writing) wavelength tuning through molecular modification and the influence of environmental conditions and thermal history on the photosensitive response observed. In general, a significant photoinduced refractive index change (with magnitude greater than 10−2 at 632.8nm) is found to be retained as the lowest energy absorption band (associated with the Group IVA conjugated backbone structure) is shifted with changes in side-group identity and backbone composition. In addition, the photosensitive response of a representative polysilane composition (poly[(methyl)(phenyl)silylene]) is observed to be strongly dependent on the local atmospheric composition during photoexposure, a key issue in the effective in-situ patterning of optical structures.