Research On Biochemical Sensing Applications Of Photonic Crystal

As building structures of photonic crystal, photonic crystal cavity and waveguide are of great importance in applications, such as sensing, optical communications, and micro optoelectronic devices. The optical properties of PhC cavity and waveguide should be researched carefully, and the coupling characteristics and theoretical model within them need investigating furthermore. Based on these analyses, the applications on biochemical sensing are involved in, including the approaches of design, optimization of the sensor devices and the experiments on it. The contents of the dissertation are as follows:The field properties of different PhC cavity modes are studied by the plane wave expansion (PWE) method, the Q factor of the cavity and the effects on it are discussed. Used the PWE method, the waveguide modes and its characteristic of the triangular lattice PhC are presented.On the basis of the time domain coupled-mode theory, the coupling characteristics of the cavity and waveguide are discussed in detail and the relation of inverse proportion between Q factor and transmission of the cavity are derived. The frequency domain theoretical model is derived by comparing photonic crystal structure to fabry-perrot cavity, and the model can be used in the sensing of biochemical of PhC; the sensor's wavelength versus refractive index fits the quasi-linear function.The biochemical sensing device are designed and optimized according to the analysis of the theory. The microcavity size is designed and optimized by the PWE method and the length of the waveguide is abtained by the FDTD methods.The optimized biochemical sensing device is fabricated by the exposure and dry etching, and the experiment of performance test is built. The results show that transmission wavelength in photonic crystal bandgap of the sensor versus the refractive index in it is quasi-linear.