OP: Spatial Light Modulation using Reconfigurable Phase Change Material Metasurfaces

OP：使用可重构相变材料超表面进行空间光调制

• 批准号: 2003509
• 负责人: Arka Majumdar
• 金额: $ 36万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2003509&HistoricalAwards=false
• 关键词: OP; Spatial; Light; Modulation; using

Many emerging applications, including autonomous driving, augmented reality visors and glass-free 3D displays rely on optical beam steering. While most existing solutions rely on mechanical movements, such as rotating a light source on top of a driverless cars, such moving parts require a large amount of energy and often limits reliability and speed. Steering light without moving parts can be extremely energy efficient, fast, and with virtually an infinite lifetime. At the heart of such a non-mechanical beam scanning technology is an optical phase shifter: a device that changes the optical path length by changing the refractive index of the material. Unfortunately, the index change of most existing materials is very small. This project aims to explore a new class of materials, called phase-change materials, which can provide almost 1000 times larger index change compared to most known materials. Moreover, the change is non-volatile, i.e., once the material is changed, the state is retained. This can reduce the energy consumption, and the complexity of the control circuit. Such materials are already being explored in the electronics community to create next-generation flash memory. This project, however, studies the optoelectronic properties of this material. To further enhance the phase shift, the project is developing hair-thin optical structures, also known as metasurfaces. These metasurfaces consist of millions of nanoscale structures that can modify incident light, and by making these structures out of phase-change materials the light beam can be steered. Along with advancing the current state of optical beam steering, this project trains a diverse, interdisciplinary workforce on novel material characterization, as well as design and nanofabrication of optical nanostructures.Shaping an optical wavefront with sub-wavelength spatial resolution is important for various applications with far-reaching scientific and technological impacts (e.g., in adaptive optics and imaging through turbid, disordered media) and commercial interests (e.g., Light Detection and Ranging for autonomous transportation and pixelated holography). The primary enabling technology for such capability is a compact optical phase shifter, which can change the phase of the incident light by a full 360 degrees at low energy (pico-Joule) and high frequency (MHz). Existing tunable optical technologies cannot provide this functionality; mechanically tunable modulators can reach a speed of only a few kHz, whereas liquid-crystal based modulators operate at 100’s of Hz. The pixel size of the spatial light modulator is also on the order of tens of wavelengths, which increases the energy consumption per pixel. To that end, this project studies emerging, non-volatile, chalcogenide-based phase-change materials and nanophotonic metasurface architectures with the goal of creating fast, low-power spatial light modulators. The sub-wavelength scatterers in a metasurface enable mapping complex curvatures onto a flat, wavelength-scale thick surface by converting them into a discretized spatial phase profile. In addition to their compact size and weight, metasurfaces are fabricated using a single-step lithography procedure with mature, highly scalable nanofabrication technology developed by the semiconductor industry. Phase-change materials can provide a large, non-volatile change in their refractive index with minimal crosstalk between neighboring pixels, as the transition only happens when a certain threshold temperature is reached. The non-volatile change also can significantly simplify the control complexity of spatial light modulators. This project combines numerical electromagnetic simulation of metasurfaces, nanofabrication, and characterization of phase-change materials and their phase transitions. The research team is developing novel metamolecule pixels and metasurface architectures and characterizing new non-volatile phase-change materials to demonstrate electronic reconfiguration of metasurfaces. This research on novel phase-change materials and their electronic reconfiguration are important to enhance our understanding of these materials and add new materials to the gamut of reconfigurable optoelectronic materials. Enhancing optical phase shifts via metamolecules and optical resonators can uncover fundamentally new knowledge on tunable nanophotonic structures and their design principles. Such design principles can be easily translated to other tunable photonic materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

许多新兴应用，包括自动驾驶、增强现实遮阳板和无眼镜3D显示器，都依赖于光束转向。虽然大多数现有的解决方案都依赖于机械运动，例如在无人驾驶汽车顶部旋转光源，但这种运动部件需要大量的能量，并且通常限制了可靠性和速度。没有移动部件的转向灯可以非常节能，快速，并且几乎具有无限的寿命。这种非机械光束扫描技术的核心是光学移相器：一种通过改变材料的折射率来改变光程长度的设备。不幸的是，大多数现有材料的指数变化非常小。该项目旨在探索一类新的材料，称为相变材料，与大多数已知材料相比，它可以提供近1000倍的折射率变化。此外，该变化是非易失性的，即，一旦材料被改变，状态就被保持。这可以降低能量消耗，以及控制电路的复杂性。这种材料已经在电子界被探索，以创造下一代闪存。然而，该项目研究这种材料的光电特性。为了进一步增强相移，该项目正在开发头发丝般细的光学结构，也称为超颖表面。这些超颖表面由数百万个纳米级结构组成，可以改变入射光，通过用相变材料制造这些结构，可以控制光束。沿着当前光束控制的发展，该项目培养了一批多元化的跨学科人才，他们将研究新型材料表征以及光学纳米结构的设计和纳米加工。形成具有亚波长空间分辨率的光学波前对于具有深远科学和技术影响的各种应用（例如，在自适应光学和通过混浊、无序介质成像中）和商业利益（例如，用于自主运输和像素化全息术的光检测和测距）。这种能力的主要实现技术是一种紧凑的光学移相器，它可以在低能量（皮焦耳）和高频率（MHz）下将入射光的相位改变整整360度。现有的可调谐光学技术不能提供这种功能;机械可调谐调制器可以达到仅几kHz的速度，而基于液晶的调制器以100 Hz的频率操作。空间光调制器的像素尺寸也是几十个波长的量级，这增加了每个像素的能量消耗。为此，该项目研究新兴的非易失性硫族化物相变材料和纳米光子超颖表面架构，目标是创建快速，低功耗的空间光调制器。超颖表面中的亚波长散射体能够通过将复杂曲率转换成离散化的空间相位分布来将它们映射到平坦的波长级厚表面上。除了其紧凑的尺寸和重量之外，超颖表面还使用单步光刻工艺制造，该工艺具有由半导体行业开发的成熟的、高度可扩展的纳米加工技术。相变材料可以提供其折射率的大的非易失性变化，同时相邻像素之间的串扰最小，因为转变仅在达到某个阈值温度时发生。非易失性变化还可以显著简化空间光调制器的控制复杂性。该项目结合了超颖表面，纳米纤维的数值电磁模拟和相变材料及其相变的表征。该研究小组正在开发新型超分子像素和超表面结构，并表征新的非挥发性相变材料，以展示超表面的电子重构。对新型相变材料及其电子重构的研究对于增强我们对这些材料的理解并将新材料添加到可重构光电材料的范围中非常重要。通过超分子和光学谐振器增强光学相移可以从根本上揭示可调谐纳米光子结构及其设计原理的新知识。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Fast and Energy‐Efficient Non‐Volatile III‐V‐on‐Silicon Photonic Phase Shifter Based on Memristors

• DOI: 10.1002/adom.202301178
• 发表时间: 2023-05
• 期刊: Advanced Optical Materials
• 影响因子: 9
• 作者: Zhuoran Fang;B. Tossoun;A. Descos;D. Liang;Xue Huang;G. Kurczveil;A. Majumdar;R. Beausoleil

Non-Volatile Reconfigurable Silicon Photonics Based on Phase-Change Materials

• DOI: 10.1109/jstqe.2021.3120713
• 发表时间: 2022-05-01
• 期刊: IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
• 影响因子: 4.9
• 作者: Fang, Zhuoran;Chen, Rui;Majumdar, Arka
• 通讯作者: Majumdar, Arka

Non-volatile materials for programmable photonics

• DOI: 10.1063/5.0165309
• 发表时间: 2023-10
• 期刊: APL Materials
• 影响因子: 6.1
• 作者: Zhuoran Fang;Rui Chen;B. Tossoun;S. Cheung;Di Liang;Arka Majumdar

Non-volatile electrically programmable integrated photonics with 5-bit operation based on phase-change material Sb2S3

基于相变材料 Sb2S3 的具有 5 位操作的非易失性电可编程集成光子学

• DOI: 10.1364/cleo_si.2023.stu3j.1
• 发表时间: 2023
• 期刊: Optica Publishing Group
• 作者: Chen, Rui;Fang, Zhuoran;Perez, Christopher;Miller, Forrest;Kumari, Khushboo;Saxena, Abhi;Zheng, Jiajiu;Geiger, Sarah J.;Goodson, Kenneth E.;Majumdar, Arka
• 通讯作者: Majumdar, Arka

A hybrid solution for spatial light modulators with a large space-bandwidth product: Opinion

• DOI: 10.1364/ome.500078
• 发表时间: 2023-07
• 期刊: Optical Materials Express
• 影响因子: 2.8
• 作者: Rui Chen;Virat Tara;A. Wirth-Singh;Abhi Saxena;Johannes E. Froech;M. Reynolds;A. Majumdar