High Throughput Tip-Enhanced Near Field Microscopy using Radially Polarized Fiber Modes

使用径向偏振光纤模式的高通量尖端增强近场显微镜

• 批准号: 1610190
• 负责人: Siddharth Ramachandran
• 金额: $ 36.07万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-15 至 2021-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1610190&HistoricalAwards=false
• 关键词: Throughput; Tip; Enhanced; Near; Field

Title: Tip-enhanced near-field microscopy using optical fiber vorticesNon-technical description: Optical microscopy is arguably one of the most successful techniques for non-invasive examination of the microscopic world ever created. In the last decade nanoscience, phenomena at length scales orders of magnitude smaller than the microscale, has played an increasingly larger role in the development of widespread technology such as nanoscale semiconductor devices, nanoparticle based therapies in medicine, and sensors that can measure minute forces and signals from biological as well as inanimate physical systems. Likewise, nanotechnology has also furthered our understanding of fundamental scientific phenomena at the nanoscale, such as the electronic structure of two-dimensional materials that promise to usher in the next generation of high-speed wearable electronic devices, images of intrinsic vibrational modes capable of sub-cellular classification and local presence of important proteins in biophysical systems. Probing, and in particular, optical probing at the nanoscale is thus of paramount importance to help lead the next revolution in science and technology much like the optical microscope did in the microscopic world. Our proposed optical fiber vortex light source will provide two to three orders of magnitude signal enhancement and background reduction in devices that can optically resolve nanoscale phenomena.Technical description: The goal of this proposed program is to develop a tip-enhanced near-field microscopy system that retains all the advantages of current scattering type near-field scanning optical microscopes, including the ability to probe the amplitude and phase response of materials in the nanometer scale using well-established elastic or inelastic scattering techniques, but with an increased throughput by several orders of magnitude (simulations suggest the possibility of 75% efficiencies, as opposed to 0.1-0.2% in current implementations). This will reduce background problems that have limited the application of current implementations of tip-enhanced microscopy systems. The primary intellectual significance of achieving program goals will be the realization of a nanoscale microscopy system that can probe signals orders of magnitude weaker than currently possible, aided by the dramatic reductions in background that an optical fiber-based nanoscale tip would enable. In the proposed effort we will use fiber tapering, electrochemical etching techniques, and precision metal deposition techniques to adiabatically convert the stable radially polarized optical modes in the fiber into plasmonic modes at the fiber tip, as required for tip-enhanced microscopy. The adiabatic mode transformation, as opposed to external illumination as is currently employed, will be the key differentiator between current tip-enhanced microscopy systems and the proposed device, as this is expected to yield the two-to-three orders of magnitude increase in signal throughput and corresponding decrease in background.

职务名称：使用光纤涡流的尖端增强近场显微镜非技术描述：光学显微镜可以说是有史以来最成功的显微镜世界非侵入性检查技术之一。在过去的十年中，纳米科学，现象在长度尺度的数量级小于微米尺度，已经发挥了越来越大的作用，在广泛的技术发展，如纳米半导体器件，纳米粒子为基础的医学疗法，和传感器，可以测量微小的力量和信号，从生物以及无生命的物理系统。同样，纳米技术也促进了我们对纳米尺度上基本科学现象的理解，例如有望引领下一代高速可穿戴电子设备的二维材料的电子结构、能够进行亚细胞分类的固有振动模式的图像以及生物物理系统中重要蛋白质的局部存在。因此，探测，特别是纳米级的光学探测，对于帮助引领下一次科学技术革命至关重要，就像光学显微镜在微观世界中所做的那样。我们提出的光纤涡旋光源将提供两到三个数量级的信号增强和背景减少的设备，可以光学解决纳米级现象。技术描述：本计画的目标是开发一种尖端增强近场显微镜系统，保留电流散射型近场扫描光学显微镜的所有优点，包括使用公认的弹性或非弹性散射技术探测纳米尺度材料的振幅和相位响应的能力，但是具有几个数量级的增加的吞吐量（模拟表明75%效率的可能性，而在当前实现中为0.1-0.2%）。这将减少限制尖端增强显微镜系统的当前实现的应用的背景问题。实现计划目标的主要智力意义将是实现纳米级显微镜系统，该系统可以探测比目前可能的信号弱几个数量级的信号，并通过基于光纤的纳米级尖端将使背景的显着减少来帮助。在拟议的努力中，我们将使用光纤锥形，电化学蚀刻技术，和精密金属沉积技术，在光纤中的稳定的径向偏振光学模式转换成等离子体激元模式在光纤尖端，尖端增强显微镜所需的。绝热模式转换，而不是外部照明，目前采用的，将是当前的尖端增强显微镜系统和拟议的设备之间的关键区别，因为这是预计将产生的两到三个数量级的信号吞吐量的增加和相应的减少背景。