Research On Temperature Characteristics Based On Hydrogel Photonic Crystal

Photonic crystals(PCs) are periodic optical nanostructures with a photonic band gap(PBG), which are made from dielectric materials. Electromagnetic waves that fall into the gap will not spread. With unique properties, photonic crystals can control transmission of light, which are promising materials for applicati on in optoelectronics and in the field of optical sensing.The band-gap properties of Photonic Crystal(PC) are affected by its dielectric layer, lattice constants, incident angle and refractive index of filled medium. When external temperature of the Thermosensitive Responsive Photonic Crystal(TRPC) is altered, the volume of the polymer gel will also change, resulting in the variation of PC lattice constants. Once the lattice constants of PC change, the band-gap properties of that will be affected, and the controllability of optical properties can be achieved. The TRPC of poly N-isopropyl acrylamide(PNIPAM) shows great potential in the field of temperature sensor due to its fast responsiveness. This paper analyzes the influence factors of photonic band-gap(PBG) in terms of theory and simulation. The preparation method and temperature response performance of Inverse Opal Thermosensitive Hydrogel Photonic Crystal(IOTHPC), which owns a wide response range, are also discussed. The main contents of this dissertation are:Firstly, the band structures of three-dimensional photonic crystal with opal and inverse opal face-centered cubic structures are analyzed. The inexistence of complete PBG of photonic crystal with opal face-centered cubic structures is verified. It’s also demonstrated that complete PBG of photonic crystal with inverse opal face-centered cubic structures exists under specific condition.Next, the Si O2 photonic crystal with face-centered cubic structures is fabricated by Self-assembly Vertical Deposition Method. The impact of layer of PC, microsphere diameter and refractive index of filled medium on PBG is analyzed by simulation and experiment. Then center wavelength of PBG hardly change as layer of PC increases while the transmissivity decreases. A bigger microsphere diameter, a smaller incident angle or a larger refractive index of filled medium will all enlarge the center wavelength of PBG.Finally, IOTHPC is prepared with colloidal crystal template(CCT) method. The equilibrium swelling ratio of PNIPAM hydrogel is measured. Then the contact between the center wavelength of PBG and temperature is built on the basis of measured equilibrium swelling ratio and Bragg-Snell formula, which is also analyzed by experiment.To sum up, this dissertation discusses the factors that have an influence on the properties of PBG with face-centered cubic structures from the perspective of theory, simulation and experiment. Additionally, IOTHPC is prepared with CCT method, and its thermosensitive characteristic is als o analyzed.