Nano-scale Manipulation Of Photons By Planar Grating Arrays And Its Applications

Currently, the realization of nano-scale manipulation of photons has two main methods. One method is the use of periodic photonic crystals to control light dispersion and transmission. Another method is to use surface plasmon binding the propagation of light and field distribution. Although the study about the basic optical element, dielectric grating, is complete, but the manipulation of photons by the arrangement of the dielectric grating in the micro-nano scale needs deep and careful study.The research work in this thesis is supported by the pre-research special project in important fundamental research of China Science and Technology Department under Grant No.2005CCA04200 and by the National Natural Science Foundation of China (Grant No.60807017). Under the supports, we have proposed two innovation structures, one with a square-lattice photonic crystal based on planar dielectric grating arrays and another with an adjacent planar dielectric subwavelength grating.The main research works are as follows:Firstly, we propose a two-dimension square lattice photonic crystal which is composed of the planar dielectric grating. With the characteristics of basic unit, we theoretically deduce the plane wave expansion algorithm formula on the basis of the electric field E in Cartesian coordinate system. The corresponding computer program is able to repeat the relative literature results, and find that the convergence is faster than the method with magnetic field expansion.The symmetry reduction approach in the presented model is to reduce the symmetry of the refractive index by sinusoidal modulation in square lattice. The band structure of three typical modulation conditions are calculated by the plane wave expansion method with electric field (E) expansion. We also investigate the influence of refractive index modulation on the formation of absolute band gaps. The results indicate that the proposed model is beneficial to create and increase absolute band gaps.Secondly, two-dimension photonic crystal (2D PC) pressure sensors are proposed. The band gap characteristics of the sensor under different pressure are thoroughly studied by PWM. The numerical results show that there is a good linear relation between the cutoff wavelength and the pressure. Apart from being easily implemented, the presented 2D PC pressure sensor holds many characteristics such as high-pressure sensitivity and convenience in achieving demanded pressure range.Thirdly, a different grating structure with two identical planar dielectric gratings adjoined by thin metallic or dielectric film, namely AG, is proposed. To calculate the diffraction properties of the structure, we first introduct rigorous coupled-wave method of the standard three-layer planar dielectric grating and repeat results in the relative literature, verifying our understanding of the rigorous coupled-wave method is correct. On this basis, rigorous coupled-wave approach is firstly expanded to analyze the two-layer grating structure. Diffractive characteristics and the near-field distribution are carried out by the numerical analysis. The surface plasmon resonance (SPR) results indicate that the AG structure has the property of multi-wavelength resonance. Moreover enhanced transmission can be excited by surface plasmon resonance (SPR) and guided-mode resonance(GMR).Finally, a wide spectrum polarization beam splitter based on adjacent grating is proposed. Owing to the characteristic of multi-wavelength resonance and transmission enhancement, TM polarization transmission spectrum and TE polarized reflectance spectrum can be achieved through designing proper parameters of adjacent grating. Furthermore, a wide resonant spectrum would be obtained by selecting the appropriate parameters, making the resonance peaks close to each other, even into one. Appropriate parameters designed to make the bandwidth of the polarization beam splitter about 20nm, if only designed to TM polarizer transmission, the bandwidth is extended to 50nm or so. Various grating parameters on the performance are also discussed.