超穎介面透鏡之研製與應用

Abstract

本研究旨在設計並實現一款具聚焦功能之可見光波段超穎介面透鏡(metalens)，並系統性探討其製程參數、封裝條件對光學效能之影響。設計上採用高折射率二氧化鈦(TiO₂)作為奈米柱材料，透過調變其橫向尺寸以實現0°至360°的相位延遲控制，並配合廣義斯乃爾定律完成聚焦之空間相位配置。模擬結果顯示，超穎透鏡在有無封裝條件下皆能有效聚焦光場，而加入光學封裝膠後不僅未造成效率明顯下降，亦未干擾相位控制，反而可進一步抑制旁瓣、提升聚焦集中度。 製程方面，採用電子束微影與乾式蝕刻技術成功製作高深寬比之奈米柱陣列，並於各製程階段進行SEM結構確認。封裝方面，採用真空輔助滲透方式提升膠體進入奈米柱間隙的能力，並透過SEM壓痕觀察佐證膠體與結構間之密合。實驗量測部分，搭建光學平台進行聚焦掃描與效率量測，實測效率達88.4 %，與模擬結果高度一致，並具良好成像解析能力。此外，即使在早期製程中曾出現部分奈米柱倒塌，其光學功能亦未完全喪失，並且具有效率46.8%，顯示本設計具良好容錯性與製程穩定性。 本研究所提出之超穎透鏡結構不僅具備高效率特性，亦驗證封裝策略對實用應用之可行性與穩定助益，為未來微型光學系統與生醫影像應用奠定關鍵基礎。

This study presents the design, fabrication, and characterization of a visible wavelength metalens with focusing functionality, and investigates the influence of fabrication and encapsulation conditions on its optical performance. The metalens consists of high-refractive-index titanium dioxide (TiO₂) nanopillars with varying lateral dimensions to achieve 0° to 360° phase modulation, based on generalized Snell's law. Simulation results demonstrate effective focusing under both encapsulated and non-encapsulated conditions. With NOA81 optical adhesive as an encapsulation layer, the device maintains high efficiency and phase accuracy, while exhibiting improved side lobe suppression and enhanced focus intensity. The fabrication process involves electron beam lithography and dry etching to produce high-aspect-ratio nanopillars. SEM imaging confirms structural integrity after each step. A vacuum-assisted encapsulation method enhances NOA81 infiltration, with imprint patterns on the cured surface serving as indirect evidence. Optical measurements show a post-lens efficiency of 88.4%, matching simulations. Even in early batches with partial pillar collapse, the lens retained focusing functionality with 46.8% efficiency, indicating strong fabrication tolerance. Overall, this work demonstrates a practical and robust metalens with high efficiency and packaging stability, suitable for compact optical systems and biomedical imaging applications.