SiO2/TiO2 omnidirectional reflector and microcavity resonator via the sol-gel method

Thin films of SiO2 and TiO2 were used to fabricate one-dimensional photonic crystal devices using the sol-gel method: an omnidirectional reflector and microcavity resonator. The reflector consisted of six SiO2/TiO2 bilayers, designed with a stopband in the near infrared. Reflectivity over an inciden t angle range of 0 degrees-80 degrees showed an omnidirectional band of 70 nm, which agrees with theoretical predictions for this materials system. Th e microcavity resonator consisted of a TiO2 Fabry-Perot cavity sandwiched b etween two SiO2/TiO2 mirrors of three bilayers each. We have fabricated a m icrocavity with resonance at lambda=1500 nm and achieved a quality factor o f Q=35. We measured a resonance frequency modulation with a change in incid ent angle of light and defect layer thickness. (C) 1999 American Institute of Physics. [S0003-6951(99)03850-4].