Fabrication Of 1D Layer Structures By Holographic Lithography And The Study Of Photoinduced Lasing

As a new kind of materials, photonic crystal which can modulate the flow of photons has attracted great attentions by material scientists, physicists and other scientists during the last decade. Moreover, a lot of research groups have devoted to designing a variety of high performance photonic crystal devices. Among the new and efficient exploration of photonic devices, the study for photonic crystal lasing is of the most particularly prominent currently. Researches showed that, lasing will easily occur at the photonic bandgap(PBG) edge and defect mode. Most reported works on band-edge lasing are from cholesteric liquid crystals (CLC), where the layered structure is constituted by chiral molecules. or 1D layered structure which fabricated by multiple coatings .Also someone fabricated the photonic crystal structure by semi-conductor growth or electron beam writing to studying band-edge lasing. In recent years, holographic lithographic technology by which can fabricate larger area photonic crystal economically, quickly and flexibly, has become an efficient method for fabricating photonic crystal templates. In this thesis, we fabricated 1D layered photonic crystal by holographic lithography single exposure method, furthermore we also got defect mode band gap. According to the band gap position should matching the organic fluorescent spectra, we doped various dyes in our fabricated 1D layered structure. By pumped pulsed laser, we investigated and observed photoinduced lasing at the band gap edge of dye-doped layered photonic crystal. Theoretical analysis of easy lasing at the band gap edge mechanism is also given in this thesis.The main contents are described as follows.1. Numerical simulation and modeling of interference pattern can set the pace for holographic lithography technic. In the article, we found that by alteration interference beams configurations and changing the polarizations of the interference beams simply, the interference patterns can be easily changed from 3D microstructures to 1D layered structure by mirror-added beams technique.2. Based on the guidance of the computer numerical simulation, we fabricated 1D layered photonic crystal in SU-8 photoresist by holographic lithography method. We can observe layered structure in the z direction by the SEM characterization which is consistent with numerical simulation results. The structures exhibit photonic band gaps in the visible range.3. We also fabricated and characterized 1D layered structures using dichromated gelatin (DCG) materials by single exposure method. These 1D photonic crystals shows very good photonic band spectrum.4. The group velocity of photons is substantially reduced when closest to the band gap edges, and the energy is gathering largely here. If the photon density of states (DOS) reached its largest value, the lasing can easily occurred. Based on the positions of band gaps and the fluorescence spectra, we doped the layered structures with different fluorescence dyes, and observed the lasing phenomenon at the edge band gap under lower threshold.