| Summary: | 碩士 === 國立交通大學 === 影像與生醫光電研究所 === 105 === Optical Tamm state is a localized surface mode that plamonic resonance occurred at the boundary between a photonic crystal and metal. We demonstrate, both simulation and experiment, the first observation of
optical Tamm state formed by cholesteric liquid crystal (CLC) and reflected metasurface. Conventional optical Tamm states have been investigated at the interface of distributed Bragg reflector (DBR) and metal. By varying the thickness of the top layer of DBR or making DBR porous, it could possibly tune the resonance wavelengths. However, it is very difficult to control the quality or modify the thickness of DBR after a sample is fabricated. Therefore, photonic liquid crystal called CLC is proposed to substitute the DBR to achieve the tunability of the resonance wavelength of the optical Tamm state, but the surface state cannot be excited directly with a photonic liquid crystal and flat metal films. The novel design of metasurfaces as reflective half-wave plates provides phase and polarization matching. At the interface between a photonic liquid crystal and a metasurface, a strong localized electric field and sharp resonance are observed. In this work, the spin selective optical Tamm
states has been accomplished. The resonance wavelength of optical Tamm states can be controlled by varying the temperature of the liquid crystal to achieve wide-range tunability.
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