Study On Fabrication Of Optical Metasurface And Optical Waveguide

With the development of micro/nano fabrication,people can design and control the optical properties of matter at nano-scale,and build new optical devices.Among them,the metasurface is a planar structure composed of subwavelength structural units,which can flexibly control the phase,polarization and wavelength of light,and it has become a research hotspot in micro/nano-optics in recent ten years.The material of metasurface has developed from early metal to high refractive index dielectric,which puts forward new requirements for fabrication technology.How to develop efficient,high-quality and high-yield manufacturing technology for different material systems has become the key to its application.In addition,high-performance optical waveguide is also the focus of integrated photonics research.Among many alternative materials,silicon is the most mature material because of its mature fabrication process,and lithium niobate has the advantages of strong electro-optical effect,high refractive index and wide transparent window,which have aroused extensive interest from researchers.In this dissertation,silicon,silicon nitride and lithium niobate are taken as the research objects,and the following researches are carried out.(1)According to the fabrication requirements of silicon and silicon nitride metasurface,by optimizing the electron beam lithography dose and dry etching parameters,the high aspect ratio metasurface which is basically consistent with the design width is fabricated.Furthermore,the imaging performance of our metasurface is characterized by the optical testing system.(2)By directly using the electron beam resist with high sensitivity as an etching mask,and by avoiding the secondary transfer of patterns,silicon waveguide can be rapidly fabricated.A dense waveguide array is fabricated by this process to realize efficient subwavelength self-imaging.At the same time,the carefully controlled lossy silicon waveguide with overlay precision better than 20 nm was prepared by electron beam lithography,and the optical simulation of imaginary-mass particles in nonHermitian system is realized.(3)Etching the lithium niobate waveguide by introducing fluorine-based gas based on argon with anti-etching electron beam resist,so as to accelerate the etching rate and improve the etching resistance of mask.The lithium niobate waveguide with a width of1?m and a height of 300 nm has been fabricated.The waveguide can pass light in experiments,and the propagation loss is 0.36 d B/mm.Furthermore,the Mach-Zehnder modulator of lithium niobate is also fabricated.