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 À2 at 632.8 nm) 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.

Effect of Photoinitiators Doped in PDMS for Femtosecond-Laser Writing: Characterization and Outcomes

“…The researchers observed that laser treatment induced chain ordering and porosity onto the PDMS surface, which resulted in a super-hydrophobic surface using a 248-nm KrF laser and a 266-nm laser. Other researchers introduced UV photosensitivity in PDMS using ultraviolet (UV) radiation, causing a bleaching reaction that severely degrades the material properties . Our approach is to obtain highly tunable integrated optical devices by enhancing the fs photoinscription response of the material without damaging the material properties.…”

“…Other researchers introduced UV photosensitivity in PDMS using ultraviolet (UV) radiation, causing a bleaching reaction that severely degrades the material properties. 20 Our approach is to obtain highly tunable integrated optical devices by enhancing the fs photoinscription response of the material without damaging the material properties. It has been demonstrated that PDMS can be laser-structured using direct writing with appropriate photoinitiators 21 , 22 and thermoinitiators.…”

Photosensitization agents for fs laser writing in PDMS

“…It can undergo a strain of 40% in the linear elastic regime and up to 170% before failure for bulk samples 7 . Laser writing on PDMS has been previously demonstrated using UV light 8 . A refractive index (RI) change (Δn) of ~ 0.14 has been reported but bleaching reaction of the PDMS was also observed resulting in degradation of the polymers chains which affects the mechanical and optical properties.…”