Study The Electron Energy Loss Spectroscopy Within Liquid Crystal

Surface plasmon is electromagnetic wave which propagation along the metal and dielectric interface,it excited by the interaction of external electromagnetic field and the free electrons of the metal material,,and in the direction of perpendicular to the metal dielectric interface, surface plasmon has exponentially decaying evanescent wave, in chemical and biological sensors, surface enhanced raman scattering, enhanced transmission subwavelength holes and other fields surface plasmon has been widely used.In fact, application of surface plasmon is achieved by changing the sizes and shapes of the metal structures and the surrounding medium parameters to modulation of the metal surface plasmon resonance.Liquid crystal material is a transition state of a part of the crystal state and a part of the liquid state.Because of its unique optical properties, it is widely used in the display area.In this paper, we put the metal nanoparticles in the environment of the liquid crystal,and study its surface plasmon in FDTD method.The surface plasmon structure in the liquid crystal has good prospect in the new photonic devices, metamaterials and biological sensors, etc.Meanwhile, the reserch of the propagation of light in a variety of nano-metal system has made great progress.In order to determine the spectral properties of various nano-metal systems,surface plasmon resonance is excited by light.It is very difficult to study the spatial model in detail in this case. But,when using the high-speed electronic to excitation, the problem can be solved. However because of the specific nature of electronic electromagnetic field leads to the theoretical modeling data of the electron energy loss spectroscopy (EELS) is more complex than optical modeling.To overcome these difficulties,the paper derives EELS theoretical model further,and studies the electron energy loss spectroscopy of metallic micro-and nanostructures in the liquid crystal environment in FDTD method.Analysis shows that modulation of the surrounding medium parameters on micro- and nanostructures surface plasmon.Details are as follows:1. The basic concepts of the surface plasmon, the development process and its applications are introduced. Followed we describes briefly the concept of liquid crystal and electron energy loss spectra.2. FDTD method is introduced in detail, including the theoretical basis and a differential format, set common excitation sources,numerical stability condition,metal dispersion model and setting absorbing boundary conditions of FDTD method,etc.3. The transmission properties of the gold column in the liquid crystal when changing the periodic structure, grating and a liquid crystal optical axis distance and other parameters is studied. The effect of these parameters of the liquid crystal optical axis angle, the periodic structure and the grating distance on surface plasmons is investigated.4. Electron energy loss spectroscopy of the metal micro-nano system is calculated by using FDTD method,and analyze the modulation of the liquid crystal, SiO2 and other media material on metal surface plasmon resonance.