Collaborative Research: NSF/ENG/ECCS-BSF: Complex liquid droplet structures as new optical and optomechanical materials

合作研究：NSF/ENG/ECCS-BSF：复杂液滴结构作为新型光学和光机械材料

• 批准号: 1711798
• 负责人: Jie Xu
• 金额: $ 14.81万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1711798&HistoricalAwards=false
• 关键词: Collaborative; Research; NSF; ENG; ECCS

Confining light to region of hundreds or even tens of micrometers in high-quality optical microresonators, one can achieve a significant concentration of electromagnetic energy. The confined light becomes much more sensitive to environmental changes, exerts an amplified mechanical force, and can generate significant nonlinear effects even at small light intensities. For this reason, optical microresonators are being actively studied in the context of optical cooling or amplification of mechanical motion, for precision metrology, lasing, ultrasensitive biosensing and other areas. Confinement of light is usually achieved using solid materials, but this project proposes to achieve it using liquid microstructures. The transition to liquid droplet creates significant challenges, but also opens up new opportunities. Firstly, mechanical softness of droplets makes them more receptive than solid materials to the light-induced forces resulting in many orders of magnitude larger mechanical responses and hence increased efficiency of optical cooling or heating. Secondly, liquid droplets allow access to the resonator's interior regions. Because electromagnetic field is orders of magnitude larger inside than outside of the resonator, one can expect the corresponding increase in sensitivity of biosensors based on droplet resonators by several orders of magnitude. Thirdly, use of liquid droplets allows realizing a novel class of photonic molecules with extra strong optical bonds based on droplet-in-droplet structures, in which one or more smaller droplets are encapsulated in a larger droplet. Overall, the objective of this project is to demonstrate the transformative potential of liquid droplet resonators in the fields of optical cooling, lasing, sensing and metrology. The interdisciplinary nature of the project, which includes physicists, and electrical and mechanical engineers, will ensure that graduate and undergraduate students will be exposed to the culture and methodology of different disciplines. In addition, the project will build connections between American and Israeli researchers and students and strengthen the collaboration between American universities participating in the project and Technion, Israel's premiere engineering school. The support for this project is provided within the collaborative NSF-BSF (Binational US-IL Science Foundation) program with participation of the Israel team financed by BSF.This project merges the fields of microfluidics and optical whispering-gallery- mode resonators by proposing the study of the optical and optomechanical properties of novel photonic structures composed of fluid droplets. The mechanical softness of liquid droplets combined with their versatility and tunability will allow the principal investigators to study novel optical and optomechanical effects such as optical cooling of capillary waves, topological energy transfer in the vicinity of exceptional points, and others. The international multidisciplinary team formed for this project will exploit state-of-the-art microfluidic technologies to fabricate different structures of droplets, with each droplet serving as a high-quality photonic resonator. Numerical simulation and theoretical models will be developed to understand the physics associated with the novel structures developed in the project. Experimentalists working on the project will carry out optical characterization of the proposed structures and develop in-depth understanding of their novel optical and optomechanical effects. This research will advance the field of optofluidics by applying state-of-the-art 3D printing technologies to the fabrication of novel microfluidic devices and generation of complex structures of microdroplets. Study of novel photonic structures with unique properties will also open new directions in the field of optical whispering-gallery-mode resonators. The general field of computational electrodynamics will also benefit from this work by taking the T-matrix formalism well outside its nominal domain and applying it to the modes of optically coupled complex structures of liquid droplets.

在高质量的光学微谐振器中，将光限制在数百甚至数十微米的区域内，可以实现电磁能量的显著集中。受限光对环境变化变得更加敏感，施加放大的机械力，并且即使在小的光强度下也可以产生显著的非线性效应。出于这个原因，光学微谐振器正在积极研究的背景下，光学冷却或放大的机械运动，精密计量，激光，超灵敏的生物传感和其他领域。光的限制通常使用固体材料来实现，但该项目建议使用液体微结构来实现。向液滴的转变带来了重大挑战，但也带来了新的机遇。首先，液滴的机械柔软性使它们比固体材料更容易接受光诱导的力，导致许多数量级的更大的机械响应，因此提高了光学冷却或加热的效率。其次，液滴允许进入谐振器的内部区域。由于谐振器内部的电磁场比谐振器外部大几个数量级，因此可以预期基于液滴谐振器的生物传感器的灵敏度会相应增加几个数量级。第三，液滴的使用允许实现基于液滴中液滴结构的具有超强光学键的新型光子分子，其中一个或多个较小的液滴被封装在较大的液滴中。总体而言，该项目的目标是展示液滴谐振器在光学冷却，激光，传感和计量领域的变革潜力。该项目的跨学科性质，其中包括物理学家，电气和机械工程师，将确保研究生和本科生将接触到不同学科的文化和方法。此外，该项目还将在美国和以色列的研究人员和学生之间建立联系，并加强参与该项目的美国大学与以色列一流工程学院Technion之间的合作。该项目的支持是由BSF资助的以色列团队参与的NSF-BSF（美国-IL两国科学基金会）合作计划提供的。该项目通过提出对由流体液滴组成的新型光子结构的光学和光机械特性的研究，将微流体和光学回音壁模式谐振器领域融合在一起。液滴的机械柔软性与其多功能性和可调性相结合，将使主要研究人员能够研究新的光学和光机械效应，如毛细波的光学冷却，异常点附近的拓扑能量转移等。为该项目组建的国际多学科团队将利用最先进的微流体技术来制造不同结构的液滴，每个液滴都可以作为高质量的光子谐振器。将开发数值模拟和理论模型，以了解与该项目中开发的新结构相关的物理学。参与该项目的实验学家将对拟议结构进行光学表征，并深入了解其新颖的光学和光学机械效应。这项研究将通过将最先进的3D打印技术应用于新型微流体设备的制造和微滴复杂结构的生成来推进光流体领域。具有独特性能的新型光子结构的研究也将为回音壁模谐振器的研究开辟新的方向。计算电动力学的一般领域也将受益于这项工作，采取T-矩阵形式主义以及其名义域之外，并将其应用到液滴的光耦合复杂结构的模式。

项目成果

Pressure of a viscous droplet squeezing through a short circular constriction: An analytical model

• DOI: 10.1063/1.5045495
• 发表时间: 2018-10-01
• 期刊: PHYSICS OF FLUIDS
• 影响因子: 4.6
• 作者: Zhang, Zhifeng;Drapaca, Corina;Xu, Jie
• 通讯作者: Xu, Jie