The Study Of Tunable Properties Of Liquid Crystal Photonic Crystals Resonant Cavity

Based on the birefringence electro-optic effect and temperature characteristic of liquid crystal,the pointing vector of liquid crystal molecules can be regulated by changing the direction of theexternal electric field and outside temperature, thereby enabling the control of liquid crystalrefractive index. When liquid crystal is introduced into a one-dimensional photonic crystal, theregulation of the liquid crystal photonic crystal defect mode can be implemented by changing thedirection of external electric field and temperature. Defect mode of one-dimensional photoniccrystal with liquid crystal is numerical calculation by using transfer matrix method in this paper.First, temperature regulation of defect modes of one-dimensional photonic crystal with aliquid crystal defect layer is numerical calculated. Firstly, a structure model one-dimensionalphotonic crystal containing a liquid crystal defect layer is created, transmission spectrum of thedefect mode and graph of defect mode wavelength varies with temperature are obtained by usingthe transfer matrix method. As the result shows: when the incident direction of polarization of theincident light is perpendicular to the direction of the long axis of the liquid crystal, the wavelengthof photonic crystal move to longer wavelengths with the increase of the temperature of thephotonic crystal, and the defect mode wavelength variation is387nm. The maximum value oftemperature sensitivity of Photonic crystal is10.9nm/k. the temperature sensitivity of the liquidcrystal defect photonic crystal is much higher than ordinary material defects photonic crystal. Itprovided the theoretic foundation for the design of one-dimensional photonic crystal resonantcavity and one-dimensional photonic crystal temperature sensor.Then, the regulation of temperature and electric field of one-dimensional liquid crystalphotonic crystal with a defect layer defect mode is studied. The characteristics of defect modesand the quality factor in one-dimensional liquid crystal photonic crystal containing a layer defectare research in detail. The transmission spectrum of one-dimensional liquid crystal photoniccrystal containing a defect layer shows that the impact of temperature on the defect modewavelength is weaker than the impact of the direction of the electric field. Temperature and thedirection of the electric field also have an impact on the quality factor. Its quality factor is muchgreater than quality factor of the ordinary resonant cavity. It is selective to the lasers. themaximum quality factor of the resonator increases as the angle θ increases. Based on theabove-mentioned characteristics, we can get the desired resonant frequency through the regulationof the electric field.Finally, temperature and electric field-control of one-dimensional gain liquid crystal photoniccrystal containing defect layer is studied. First structure model of one-dimensional gain liquidcrystal photonic crystal containing defect layer and the gain model of ZnO medium are established. The numerical analysis shows before and after the pump of ZnO, the energy band structure of thephotonic crystal has not changed comparing the result in Chapter four, and the position of thedefect mode has not also changed, but the transmittance of the defect mode has changed.