Microsphere Photolithography Patterned Nanohole Array on an Optical Fiber
Microsphere Photolithography Patterned Nanohole Array on an Optical Fiber
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DOI：
10.1109/access.2021.3059439
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发表时间：
2021-01-01
期刊：
影响因子：
3.9
通讯作者：
Almasri, Mahmoud
中科院分区：
文献类型：
--
作者：
Jasim, Ibrahem;Liu, Jiayu;Almasri, Mahmoud
微球光刻（MPL）是一种纳米图案化技术，其利用微球的自组装单层作为光学元件来将入射辐射聚焦在光致抗蚀剂层内。微球在每个微球的与照射相对的一侧上产生亚衍射限制的光子射流。当结合图案转移技术，如蚀刻/剥离，MPL提供了一个通用的，低成本的制造方法，用于生产六方密堆积超颖表面。本文研究了MPL过程中创建折射率（RI）传感器的光纤切割尖端。表面上的金属元素的共振波长取决于局部介电环境，并允许光谱解析分析物的折射率。金属薄膜中的孔阵列的数值研究表明，波导模式提供了良好的灵敏度分析物的折射率。这可以很容易地调整通过调整MPL曝光和模拟结果指导制造的缺陷容忍折射率传感器的光纤尖端的尖端与613 nm/RIU的灵敏度。微球单层的共形性质简化了制造过程，并提供了一个可行的替代直写技术，如聚焦离子束（FIB）铣削。
Microsphere Photolithography (MPL) is a nanopatterning technique that utilizes a self-assembled monolayer of microspheres as an optical element to focus incident radiation inside a layer of photoresist. The microspheres produces a sub-diffraction limited photonic-jet on the opposite side of each microsphere from the illumination. When combined with pattern transfer techniques such as etching/lift-off, MPL provides a versatile, low-cost fabrication method for producing hexagonal close-packed metasurfaces. This article investigates the MPL process for creating refractive index (RI) sensors on the cleaved tips of optical fiber. The resonant wavelength of metal elements on the surface is dependent on the local dielectric environment and allows the refractive index of an analyte to be resolved spectrally. A numerical study of hole arrays defined in metal films shows that the waveguide mode provides good sensitivity to the analyte refractive index. This can be readily tuned by adjusting the MPL exposure and the simulation results guide the fabrication of a defect tolerant refractive index sensor on the tip of a fiber tip with a sensitivity of 613 nm/RIU. The conformal nature of the microsphere monolayer simplifies the fabrication process and provides a viable alternative to direct-write techniques such as Focused Ion Beam (FIB) milling.