【作者】 余鑫；

【导师】 沈云；

【作者基本信息】 南昌大学 ， 光学， 2021， 硕士

【摘要】 在科技飞速发展的今天,人们对仪器设备、军民用品的小型化和轻便化的追求越发强烈。电磁波的调控,一直以来都是通过不同厚度的介质产生相位累积来调节的。但是超表面的诞生改变了这一现状,可以通过人工调节材料的参数从而实现对电磁波的调节,并且可以有效的解决传统光学器件体积大、加工成本高等问题。超表面作为一种新型人工材料,它可以在亚波长尺度对光束的相位、振幅和偏振进行调控,打破了对传统光学器件依赖。超表面结构相对于传统的光学元件,显示了新颖的光学现象,并具有更紧凑结构和更简单的制备工艺,具有空间相位调节的能力,可以对光波阵面进行任意调控。本文描写了电磁波调控和超表面的相位控制的进展。从实现完整0-2π相位操纵的基础物理学出发,讨论了此类超表面在光子学中的应用,并讨论了该领域的未来前景。本文设计了一种太赫兹波段在1.1 THz处实现良好聚焦效果的相位梯度超表面透镜。通过对V型天线基本单元的设计以实现相位梯度0-2π的覆盖,可以实现对太赫兹波的定向调控。并且对比了不同偏振的入射光,我们的超表面透镜可以实现大数值孔径、偏振不依赖的聚焦效果。基于微纳加工工艺完成太赫兹超表面透镜的实验制备。并且基于太赫兹近场显微镜进行实验测量,对比不同数值孔径的太赫兹透镜我们实现了较高的分辨率最高可达206μm。理论和实验结果相吻合,可以应用于集成光学和测试系统中代替传统太赫兹透镜。更多还原

【Abstract】 Today,with the rapid development of science and technology,people are increasingly pursuing the miniaturization and portability of instruments and equipment,military and civilian supplies.The adjustment of electromagnetic waves has always been adjusted through the accumulation of phases generated by media of different thicknesses.However,the birth of metasurfaces has changed this situation.The electromagnetic wave can be adjusted manually by adjusting the parameters of the material,and it can effectively solve the problems of large volume and high processing cost of traditional optical devices.As a new type of artificial material,the metasurface can control the phase,amplitude and polarization of the beam at the sub-wavelength scale,breaking the dependence on traditional optical devices.Compared with the traditional optical elements,the metasuperface structure shows novel optical phenomena,and has a more compact structure and simpler preparation process,has the ability to adjust the spatial phase,and can adjust the light wave front arbitrarily.This article describes the progress of electromagnetic wave control and phase control of metasurfaces.Starting from the basic physics for realizing complete 0-2πphase manipulation,the application overview of such metasurfaces in photonics is discussed,and the future prospects of this field are discussed.In this paper,a phase-gradient metasurface lens that achieves a good focusing effect at 1.1 THz in the terahertz band is designed.Through the design of the basic unit of the V-shaped antenna to achieve the coverage of the phase gradient of 0-2π,the directional control of the terahertz wave can be realized.And compared with the incident light of different polarizations,our metasurface lens can achieve a large numerical aperture and polarization-independent focusing effect.The experimental preparation of the terahertz metasurface lens is completed based on the micro-nano processing technology.And based on the terahertz near-field microscope for experimental measurement,we have achieved a higher resolution of up to 206 μm by comparing terahertz with different numerical apertures.The theoretical and experimental results are consistent and can be used in integrated optics and test systems to replace traditional terahertz lenses.更多还原