Research On The Characteristics Of The Guided-mode Resonances In Dielectric Subwavelength Gratings

The binary optical elements (BOE's) of subwavelength microstructures hold several specific properties beyond the ordinaries. One can use this type of BOE's to develop such those well-performed BOE's as total-reflectors, antireflectors, filters and polarizing-splitters. The advent of subwavelength-microstructure BOE's led to a new stage for the micromechanics and binary optics. In analyzing the subwavelength-microstructure BOE's, the vector diffraction theory must be used in that the dimension is of or under the magnitude of incident wavelength. Considering the periodic-structured elements, which called subwavelength diffractive gratings, the guided-mode resonances with narrowband occur on certain conditions. These elements can then be used into line-narrow lasers in bulk system and possibly in integrated optics.In this paper, the characteristics of guide-mode resonances in dielectric subwavelength gratings are analyzed by using mode-matching method. The main studies can be summarized as follows: the mode-matching method combining with the Fourier factorization rules and the recursion algorithm of reflective and transmissive coefficient matrix is introduced to study the physical whys and the specific properties of guided-mode resonaces; a calculating program, which is fast and stable enough to be a useful tool for the following researches, is compiled based on our vector theory; by using this program, a new type of polarizing splitter and a new type of filter are designed according to the characteristics of narrowband, spectral and angular sensitivities of resonant grating; for the excellent function on mode-selection, we venture the latter into the application of mode-selector in laser cavity.