Germanium metalens for longwave infrared applications

IF 3.1 3区物理与天体物理 Q2 Engineering

Optik Pub Date : 2024-10-16 DOI:10.1016/j.ijleo.2024.172087

J.M. Borlido , E.M.F. Vieira , J.H. Correia , J.A. Rodrigues

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引用次数: 0

Abstract

Metalenses represent a paradigm shift in optics, offering unprecedented control over light manipulation. This study focuses on the design optimization of a polarization-insensitive germanium (Ge) metalens operating in the longwave infrared (LWIR) regime. Employing rigorous coupled-wave analysis (RCWA) and finite-difference time-domain (FDTD) simulations, a metalens with 1 mm focal length was designed using nanopillars with 3.5 µm height and radius ranging from 0.55 µm to 1.2 µm. Then, the impact of lattice size and numerical aperture (NA) on lens performance was investigated. The results indicate that smaller lattices allow finer phase control and enhanced transmittance stability across the phase profile if significant coupling effects are not verified. As the NA increases, the focal spot size decreases, albeit with diminishing returns towards the diffraction limit. To the best of our knowledge, it is the first work that shows high focal efficiency (∼80 %) across multiple NA's for a LWIR metalens with a diameter under 1100 µm. The proposed metalens is compatible with complementary metal-oxide-semiconductor (CMOS) technology and supports low-cost manufacturing.

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用于长波红外应用的金属锗

金属透镜代表了光学领域的范式转变，为光操纵提供了前所未有的控制能力。本研究的重点是对工作在长波红外（LWIR）波段的偏振不敏感锗（Ge）金属透镜进行设计优化。利用严格的耦合波分析 (RCWA) 和有限差分时域 (FDTD) 模拟，使用高度为 3.5 µm、半径为 0.55 µm 至 1.2 µm 的纳米柱设计了焦距为 1 mm 的金属膜。然后，研究了晶格尺寸和数值孔径（NA）对透镜性能的影响。结果表明，如果没有验证显著的耦合效应，较小的晶格可以实现更精细的相位控制，并增强整个相位剖面的透射稳定性。随着 NA 的增大，焦斑尺寸也随之减小，但在衍射极限时，焦斑尺寸会逐渐减小。据我们所知，这是第一项工作，显示了直径小于 1100 微米的 LWIR 金属膜在多个 NA 范围内的高聚焦效率（∼80%）。拟议的金属膜与互补金属氧化物半导体（CMOS）技术兼容，支持低成本制造。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Optik 物理-光学

CiteScore

6.90

自引率

12.90%

发文量

1471

审稿时长

46 days

期刊介绍： Optik publishes articles on all subjects related to light and electron optics and offers a survey on the state of research and technical development within the following fields: Optics: -Optics design, geometrical and beam optics, wave optics- Optical and micro-optical components, diffractive optics, devices and systems- Photoelectric and optoelectronic devices- Optical properties of materials, nonlinear optics, wave propagation and transmission in homogeneous and inhomogeneous materials- Information optics, image formation and processing, holographic techniques, microscopes and spectrometer techniques, and image analysis- Optical testing and measuring techniques- Optical communication and computing- Physiological optics- As well as other related topics.