Research And Application Of Micro-nano Structures For Electromagnetic Manipulating

With the rapid development of nanophononics in recent years,the demand for miniaturization and integration of optical devices is increasing.Traditional optical devices,which are constrained by factors such as the material itself and diffraction effects,have limited its design and application at nano scales.In recent years,the development of metasurface and waveguide resonator structures has enabled researchers to expand the design and research ideas for electromagnetic wave frontwave control and micro-nano sensor.And provides new ways for the miniaturization and integration of optical devices.This paper is based on the above research background and studied the electromagnetic metasurface which composed of rectangular silicon nanoantennas and waveguide resonator structure.We analyzed the mechanism of interaction between the electromagnetic wave and the two kinds of micro-nano devices and simulated the model by simulation software.Finally,the structural optimization of the two kinds of devices was performed.The specific research content is as follows:1.We analyzed the scattering of electromagnetic waves by the rectangular silicon nanoantenna on silica substrate.Firstly,we discuss the influence of length,width,height and rotation angle of silicon nanoantenna when circularly polarized electromagnetic waves incident from below the silica substrate.In simulations,changing the geometric parameters of the nanoantenna has a significant effect on its electromagnetic response.When the length,width and height increase respectively,the transmittance curves produce a red shift,and the peak value of the transmittance in a certain wavelength range increases.The phase of the outgoing electromagnetic wave can be changed within the range of 0-2π by rotating the direction of the nanoantenna.This kind of linear modulation of the phase of the wavefront is very beneficial to the wavefront control of the electromagnetic wave.When the incident wave is left-handed circularly polarized wave,we detected right circularly polarized wave in outgoing port.The simulation proves that the silicon nanoantenna has good at polarization conversion characteristics.We use the electric dipole and magnetic dipole theory to analyze the resonance mechanism of the silicon nanoantenna and discuss the internal mechanism of the electromagnetic response of the silicon nanoantenna.Finally,we studied that the silicon antenna was filleted to verify the effect of processing accuracy on the silicon nanoantennas.In simulation,we found that the silicon nanoantenna had a good processing tolerance,and its performance was not fundamentally affected in the case of passivation.2.Use the optimized size nanoantennas to form a functional metasurface.Firstly,based on general Snell’s theorem,the working mechanism of anomalous refraction super surface is analyzed,and the anomalous refraction metasurface realized by phase discontinuity is designed and verified.We have further designed a three-way spectroscopic metasurface,and simulations have verified that different phase delays on the metasurface can cause different outgoing light deflection angles in different regions to achieve the spectroscope.Then,using the nanoantenna’s linear phase modulation characteristic of the wavefront,a single-focus metasurface was designed by calculating the phase delay.Finally,the double-focusing super surface is designed by using array and holographic methods,respectively.Based on the double-focusing super-surface,the three-focusing,four-focusing metasurfaces are continuously designed using computational holography.The above metasurfaces are all simulated by software and the expected simulation results are obtained.3.Based on previous two-dimensional MIM waveguides,we have expanded and studied the structure of rectangular waveguide resonators in the near-infrared band at the first time.By extending the vertical direction of the resonant cavity of the MIM waveguide and adding two cover plates to form a rectangular waveguide resonant cavity structure,a function similar to a band-pass filter is formed.In this paper,a comparative study of a cylindrical cavity and a baffled cylindrical cavity is conducted.We discussed the influence of the height of the resonator and the length of the baffle in the resonator on the characteristics of the structure.When the height of the structure and the length of the baffle increase,the peak of the transmission curve will produce a significant red shift,and with the increase of the length of the baffle,the peak value of the transmittance will decrease significantly.In the simulation,when the baffles were added,the transmission curve moved more violently regardless of the height or refractive index of the cavity,indicating that the sensitivity of the entire device increased.Through the above discussion on the rectangular waveguide resonator,it lays a good foundation for the research and design of similar devices in the future.