Research Of Terahertz And Optical Devices Based Surface Plasmon Polaritons

Surface plasmon polaritons(SPPs) based on sub-wavelength metallic arrays, and terahertz(THz) technology, are currently research hotspots and difficulty problems. Generally, the spatial resolution of the THz imaging detection is much lower than that of optical approaches because of the strong diffractive limit of THz waves with longer wavelength. It will play a very important role in realizing the integrated imaging detection of the optical and radio electromagnetic waves through combining the SPPs and lightwave properties in THz and visible and infrared wavelength range according to subwavelength focusing and thus breaking diffractive limit effect. This dissertation proposes several methods for SPPs devices suitable to an extremely broad frequency range including typical THz, infrared and visible wave through sub-wavelength metallic arrays and fabricating both the THz and optical SPPs devices. The main works are as follows:(1) Based on the subwavelength metal aperture,four kinds of subwavelength wedge aperture micro-structures have been designed, and further the four kinds of sub-wavelength metallic arrays have been established, and continuously a kind of THz-SPPs and a type of optical SPPs have been constructed through fusing the sub-wavelength metallic arrays and micro-grating-structures.(2) Using finite element method and adaptive mesh refinement techniques, the electromagnetic properties, for instance the reflectivity, the electricfield distribution and the electric current distribution, have been simulated. Through discussion the effectiveness of SPPs stimulated by the devices developed, and the SPPs characteristics of light field resonance and the local eleectricfield enhancement, and the problem that the local structural parameter variance of devices will affect the characteristics of SPPs, are explored carefully.(3) Considering the encapsulation requirements and the array size of subwavelength metal structures, the parameter system of the THz-SPPs has been set up. Based on the standard microelectronics technology, the THz-SPPs devices are designed and fabricated successfully. Through comparing the electron beam lithography with the focused ion beam etching, the technological process flow and design specification of optical SPPs, are determined.(4) Using THz time-domain spectroscopy technology and near-field scanning microscope,both the transmission characteristics and the near-field light distribution of the THz-SPPs have been measured, respectively. According to the analysis of simulation and measurement results, a roadmap of techniques constructed by us, has been proposed.