940nm波段之超穎表面極化分光器

Abstract

在光學應用中，偏振分束器（PBS）起著至關重要的作用，常用於與偏振方向相關的感測、數據存儲、通訊、成像和信號處理任務中。為了克服傳統PBS經常受限於鏡片厚重的問題。因此，我們利用電腦計算能力結合半導體製程技術，製作出一種亞波長尺寸的人造結構，稱之為超穎透鏡。超穎透鏡可以透過不同線寬的奈米柱的排列，輕易的改變入射光的偏振、相位、幅度和色散，進而獲得操縱光的能力。因此，通過設計這些不同尺寸奈米柱的排列方式，來實現超穎透鏡的多樣性應用。 在本篇論文中，我們利用商業軟體 Ansys Inc.的時域有限差分（FDTD）和Zemax OpticStudio 的幾何光學設計軟體，進行超穎透鏡的設計和模擬。首先，使用FDTD建構出奈米柱的資料庫，並且利用Python將資料庫的數據進行擴增。接著，利用Zemax進行超穎透鏡的結構參數優化，進而模擬出超表面PBS的真實情況。最後，依靠製程技術，製作出超穎透鏡的樣品，並且進行量測分析。 根據研究結果顯示，我們所設計的超表面PBS在模擬上，具有最大±45度角的光束偏折能力。另外，經過實際的量測分析後，也將我們的模擬解果進行驗證。因此，這項研究展示了基於超表面 PBS 的設計，能在更加輕薄的體積下進行光束的操縱，具有實現所需偏折角度和功率分佈特性方面的潛力。為未來在相關的感測、數據存儲、通訊、成像和信號處理任務中，提供了另一種解決方案。

In optical applications, the polarization beam splitter (PBS) plays a important role, generally used in tasks related to data storage, polarization-dependent sensing, imaging, communication, and signal processing. To overcome the limitation of conventional PBS often constrained by bulky lenses, we utilized computational capabilities combined with semiconductor manufacturing technology to create a subwavelength-sized artificial structure called a metalens. The metalens can easily alter the polarization, phase, amplitude, and dispersion of incident light by arranging nanorods with different linewidths, thereby achieving the ability to manipulate light. By designing these arrangements of nanorods with varying sizes, diverse applications of the metalens can be realized. In this paper, we used the commercial software Ansys Inc.'s finite-difference time-domain (FDTD) and Zemax OpticStudio geometric optics design software to design and simulate the metalens. First, we constructed a nanorod database using FDTD and expanded the data using Python. Then, we optimized the structural parameters of the metalens using Zemax and simulated the real situation of the metasurface PBS. Finally, relying on manufacturing technology, we fabricated the metalens sample and conducted measurement analysis. The research results show that the metasurface PBS we designed in the simulation has a maximum beam deflection capability of ±45 degrees. Furthermore, after conducting actual measurement analysis, we validated our simulation results. Therefore, this study demonstrates that the design of the metasurface PBS can manipulate beams in a more compact volume, showing potential in achieving the required deflection angle and power distribution characteristics. It provides another solution for future applications in related data storage, sensing, imaging, communication, and signal processing tasks.