Controlling Light Polarization And Transmission Properties With Nano Resonators And Their Composite Structures

With the development of the new generation of optoelectronic devices, integrated industry, nano-photonics and -technology, quantum information, and so on, constructing nanostructure to manipulate and control light and developing smaller, faster and better novel photonic devices have become the focus of international research frontiers and new-technology competition. Nano resonators have particular amplitude and phase responses to the light interacting on them. By adjusting their relevant structure parameters, the polarization or transmission properties of light can be effectively controlled. The photonic devices constructed by these resonators not only improve the performance of traditional devices but also implement other new functions. Typical nano resonators are nano metal particles, quantum dots (QDs), nanocavities, etc. In this thesis, we focuses on novel nano photonic devices design. By investigating the properties of resonance and coupling interaction between the resonators, we design nano resonators and their composite structures to effectively control the polarization or transmission properties of light. That is, we aim at designing novel polarization and transmission control systems based on nano resonators.The main research achievements of this thesis are summarized as follows:1、The response properties of single nano metal particle, particle dimer and particle trimer to light are analyzed analytically. This makes the physical view of the interaction between nano metal particles and light become clearer and easier to understand. And it laies foundation for understanding the design of nano metal composite structures to realize light properties control.2、Based on the polarization characteristics of scattered light of single V shape nano mental particle, a design scheme of nano plasmonic metasurface radially/azimuthally polarized beam generator is proposed. The design condition satisfied by the elementary structure parameters is given. According to this condition, two transmissive and a highly efficient reflective radially/azimuthally polarized beam generators are designed which are respectively constructed based on the V shape, the Y shape particles and the elliptical shape Au particles-MgF2-Au substrate plat. And relevant numerical simulations for these generators properties are performed.3、Controlling SPP (Surface Plasmon Polaritons) transmission properties in double QDs coupling silver nanowire (AgNW) system and double nanocavities coupling metal-dielertric-metal (MDM) waveguide system are both theoretically analyzed. Combining the advantages of the two control systems, single QD coupling FP nanocavity system for controlling SPP transmission in AgNW-PMMA-Ag substrate waveguide structure is designed. A sharp Fano lineshape appears in the stop band of the transmission spectrum of the entire structure. And the factors influencing on the lineshape are analyzed.4、Based on coupled mode theory, the design theory of trigonometric function modulation PT-symmetry-like unidirectional reflectionless waveguide is analyzed. We extracted an essential condition for achieving unidirectional reflectionless phenomenon:unidirectional mode coupling. According to this condition, a PT-symmetry-like unidirectional reflectionless ternary layered structure is designed. A concise necessary and sufficient condition satisfied by the structure parameters is derived in theory and demonstrated in numerical simulation. The underlying mechanism for unidirectional reflectionless phenomenon is also given from the angle of the interference between electric field modes.The highlights of this thesis are as follows:1、A novel and highly efficient reflective radially/azimuthally polarized beam generator constructed based on elliptical shape Au particles-MgF2-Au substrate plat is designed. The reflectivity (conversion efficiency) can be achieved above 70%. The thickness of the entire structure is in deep subwavelength range. The performing wavelength can be modulated in entire visible-frequency range. The design idea and steps are simple, clear and understandable. The work has some inspiration and reference significance in other novel nano optical devices design.2、Single QD coupling high-Q FP nanocavity system for controlling SPP transmission in AgNW-PMMA-Ag substrate waveguide structure is designed. The entire structure possesses the characteristics:1、It supports a gap mode locally bounded between the AgN W and Ag substrate. This mode has strong locality and less loss. This improves the coupling efficiency between the QD and the nanocavity.2、 For the narrow spectral response characteristic of QD, the Fano lineshape in the transmission spectrum is very sharp.3、The FP cavity in the structure is formed by two distributed bragg gratings. This provides a relatively flat background for the Fano lineshape in the transmission spectrum. And it enhances the lineshape transmissivity change contrast.3、The PT-symmetry-like unidirectional reflectionless ternary layered structure is designed and it realizes the spatial separation between the real and the imaginary modulation materials. The structure is constructed with only three kinds of materials which improves the availability of natural material. The layered characteristic of the structure reduces the difficulty of its practical fabrication and makes the structure have strong practicability. An essential condition for achieving unidirectional reflectionless phenomenon is extracted during the design process. The concise sufficient and necessary condition satisfied by the structure parameters is given. The formation of unidirectional reflectionless phenomenon is explained from the angle of the interference between electric field modes. All these theoretical analyses will have important inspiration significance in other unidirectional transmission structure design.