Research On The Photophysical Process Modulated By The Photonic Band Gap

Photonic crystals have attracted attentions in research fields with the properties ofphoton localization and photonic band gap (PBG). The photophysical processes ofphotoelectric materials can be modulated by photonic band gap, so some peculiarphenomena and optical behaviors have been observed and analyzed. Besides theirpotential in constructing new photonic devices, photonic crystals provide a newopportunity to modify photophysics processes. In this paper, the modulation on thephotophysics process, such as spontaneous emission and energy transfer, wereinvestigated by the theoretical and experimental methods. The key findings andinnovation points of this dissertation are as follows:Based on the theoretical research on spontaneous emission modulated by PBG, thesimulation of the density of states was analyzed. The energy transfer process in PBGwas investigated by both the quantum theory and statistical dynamics. The theoreticalmodels of energy transfer process in PBG were built to describe the modulationmechanism. The fluorescence decay curves of donor were numerical simulated byMonte-Carlo method based on the theoretical models. It showed the modulationmechanism of PBG in the photophysics process.The Tb3+, Eu3+co-doped inverse opal photonic crystal samples were prepared byself-assemble combined sol-gel methods. The energy transfer efficiency with andwithout PBG was investigated through fluorescence spectra and donor’s fluorescencelifetime. It was proved that the PBG enhanced energy transfer when the fluorescenceemission wavelength of Tb3+overlaps the PBG, the fluorescence intensity of Tb3+issuppressed, and the fluorescence intensity of Eu3+is increased. Additionally, it was thefirst reported that fluorescence lifetime of Tb3+decreased due to modulation of PBG.A new experimental method to study the spontaneous emission modulated by PBGis proposed based on continuous shift of PBG. The spontaneous emission intensity wasmonitored by time acquisition channel during the PBG shift continuously. Themodulation effected by DOS was discussed in the band gap or near the band gap edge.Temperature tunable photonic band gap crystals were prepared by a new methodbased on the tuning effective refractive index by temperature. Compared with former methods, it can be tuned continuously and responsively in a wide range with convenientmeans. The Tb3+doped tunable PBG samples were fabricated for the research onspontaneous emission. The PBG was tuned by temperature to change the relativelocation δ with spontaneous emission peak. The modulation effects were discussed byfluorescence spectra.