基于非对称金属包覆介质波导的纳米光刻理论研究

发布时间：2018-05-20 23:35

本文选题：非对称金属包覆介质波导 + 表面等离子体　；参考：《兰州理工大学》2017年硕士论文

【摘要】：本文基于非对称金属包覆介质波导,使用棱镜激发该结构中的导模,刻写一维亚波长光栅和二维多层亚波长光子结构。通过分析导模的色散曲线和导模干涉光场分布图,研究一维亚波长光栅和二维多层亚波长光子结构的周期与相关参数的关系。该制备方法成本低廉,操作简单,产出高,为这两种微纳结构的广泛利用提供了重要的理论参考,并且为以后在实验中刻写制备多层亚波长光子结构提供了一种可能的方法。具体研究内容如下:(1)用325nm波长的激光激发由Al膜,光刻胶,和空气组成的非对称金属包覆介质波导结构中的零阶导模,来刻写不同周期,不同深宽比的亚波长光栅。通过零阶导模色散曲线理论分析和有限元方法数值模拟,发现改变光刻胶的厚度和折射率,导模的偏振可以刻写不同周期和不同深宽比的亚波长光栅,并且刻写的亚波长光栅最小周期能够达90nm。(2)基于非对称金属包覆介质波导,利用棱镜耦合方式激发该结构中的TE0导模,通过两束TE0导模干涉,从而在理论上实现刻写周期可调的亚波长光栅。在研究中,我们用TE0导模的色散曲线,研究了TE0导模刻写的亚波长光栅周期与激发光波长、光刻胶厚度和折射率、棱镜之间的关系。再用有限元方法模拟的非对称金属包覆介质波导中TE0导波模式的干涉电场分布进行验证。最后,将TE0导模干涉光刻与表面等离子体干涉光刻进行比较,发现由于TE0导模穿透深度相较于SPP更大,故而可实现在厚光刻胶条件下,改变激发光波长、棱镜折射率、光刻胶折射率、尤其是光刻胶厚度等方法有效调控亚波长光栅的周期。(3)理论研究高阶导模干涉刻写不同周期和层数的多层亚波长光子结构。442nm波长的激光作为激发光源激发非对称金属介质波导中的高阶导模。理论分析导模的色散曲线和数值模拟的导模干涉场分布,详细研究多层亚波长光子结构的周期与光刻胶的厚度和折射率,高阶导模的模序数和偏振的关系。这种制备方法不仅可以制备不同周期和层数的多层亚波长光子结构,而且它的过程简单,成本低廉。
[Abstract]:Based on the asymmetric metal-coated dielectric waveguide, the guided mode of the structure is excited by prism, and the 2-D multilayer subwavelength photonic structure is described. By analyzing the dispersion curve of the guided mode and the light field distribution of the guided mode interference, the relationship between the periodicity and the related parameters of the 1-B wavelength grating and the two-dimensional multilayer sub-wavelength photonic structure is studied. This method has the advantages of low cost, simple operation and high output, which provides an important theoretical reference for the wide use of these two microstructures, and provides a possible method for the fabrication of multilayer sub-wavelength photonic structures in the future. The specific research contents are as follows: (1) the zero-order guided mode in the asymmetric metal-coated dielectric waveguide structure composed of Al film, photoresist and air is excited by 325nm wavelength laser to write subwavelength gratings with different periods and different aspect ratios. By theoretical analysis of zero-order guided mode dispersion curve and numerical simulation by finite element method, it is found that by changing the thickness and refractive index of photoresist, the polarization of guided mode can be characterized by subwavelength grating with different periods and ratio of depth to width. And the minimum period of the subwavelength grating can be up to 90nm.m-2) based on the asymmetric metal-coated dielectric waveguide, the TE0 guided mode in the structure is excited by prism coupling mode, and the interference is achieved by two TE0 guided mode interference. Thus the subwavelength grating with adjustable writing period can be realized theoretically. In the study, we use the dispersion curve of TE0 guided mode to study the relationship between the period of subwavelength grating and the wavelength of excited light, thickness of photoresist and refractive index, prism. The interference electric field distribution of TE0 guided wave mode in asymmetric metal-clad dielectric waveguide was simulated by finite element method. Finally, by comparing the TE0 guided mode interference lithography with the surface plasma interference lithography, it is found that because the penetration depth of the TE0 guide mode is larger than that of the SPP, it can be realized under the condition of thick photoresist to change the excited light wavelength and the refractive index of the prism. Refractive index of photoresist, Theoretical study on the effective Control of the period of Subwavelength grating by photoresist thickness) theoretical study of higher-order guided mode interferometry with different periods and layers of multi-layer sub-wavelength photonic structure. 442 nm wavelength as excitation source to excite asymmetric light High order guided modes in metallic dielectric waveguides. The dispersion curve of guided mode and the distribution of guided mode interference field in numerical simulation are analyzed theoretically. The relationship between the period of multilayer sub-wavelength photonic structure and the thickness and refractive index of photoresist, the mode number and polarization of high-order guided mode is studied in detail. This method can not only fabricate multilayer sub-wavelength photons with different periods and layers, but also have simple process and low cost.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN25

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