Characteristics Of Subwavelength Optical Elements And Applied Research

Diffractive optical elements with subwavelength grating structures have been a subject of great interest in binary optics for many years. Especially, after guided-mode resonance in waveguide grating was presented and studied more detailed, this kind of optical elements has attracted a large of researchers. Utilizing the guided-mode resonance effect, optical filters, polarizing splitters and conversers etc. of high quality can be designed, which can advance the development of optical communications and correlative optical areas.In this dissertation, the rigorous diffractive theory, Fourier mode method, is presented firstly. Then, the guided-mode resonance effects associated with waveguide gratings are studied completely. Based on this characteristic, simultaneously satisfying the anti-reflection condition, narrow-linewidth reflection bandstop filter with low sidebands is designed. On the other hand, integrating of the resonant waveguide grating into a thin-film high/low permittivity quarter-wave pairs with highly reflective efficiency, narrow-linewidth transmission bandpass filter is obtained. To realize the unpolarized filtering applications a triangle-profile surface-relief grating structure is presented. According to certain parameters, this structure can highly reflected the incident wave, regardless of the incident polarization, TE or TM polarized. Broad-linewidth filters are widely used in many areas. The grating multilayer structure that the ridge of grating in each period is form of thin-film high/low permittivity pair is introduced. Based on the guided-mode resonance effect of waveguide grating and the interference of multi-films, the reflection bandstop filters designed have wide linewidths. In addition, broad-linewidth reflection bandstop filter with one-layer grating structure is designed by use of optimization technology for diffractive optical elements and rigorous grating diffractive theory. Finally, rigorous theory is used to analyze photonic crystals for their subwavelength periodic structures. Based on the structural properties, multi-grating model is presented to simply calculation process. According to the model a program is compiled to discuss the bandgap characteristics for several kinds of two-dimensional photonic crystals. Furthermore, one-dimensional photonic crystals are studied by using the eigen matrix method.