MRI: Acquisition of a Cryogenic Scanning Near-field Optical Microscope with Spatially Resolved Fourier Transform Infrared Spectroscopy

传统光学显微镜的分辨率被限制在大约光波长的一半。该主要研究仪器项目获得了最先进的扫描近场光学显微镜，可以对冷却到液氦温度的纳米材料进行光学研究，并以超过10倍的空间分辨率绘制化学成分图。显微镜的工作原理是将光源聚焦到金属化的尖端，并通过等离子激发增强局部电场。显微镜检测后向散射光作为位置的函数来绘制样品的光学特性图。独特的仪器功能有助于将亚利桑那大学建立为一个区域和国家中心，对来自美国各地的用户广泛访问材料的光学特性。显微镜的增加提供了尖端的学生培训，教育和劳动力发展机会，并导致物理学，材料科学，光子学，生命科学和行星科学的进步。该仪器还在凤凰城与春季材料研究协会会议联合举办的年度研讨会上展出，并在学生和其他早期职业研究人员的年度暑期扫描探针显微镜培训课程中使用，其中许多人来自科学和工程领域代表性不足的群体。扫描近场光学显微镜补充了亚利桑那大学的一套多用户系统，用于在大空间和能量尺度上表征纳米材料。技术描述扫描近场光学显微镜具有几个独特的功能，例如能够达到低于10 K的温度，以亚波长分辨率执行空间分辨傅立叶变换红外光谱，使用可见和近红外源执行近场测绘，并执行尖端增强光致发光测量。该显微镜支持广泛的研究项目，包括：(1)原子薄材料中的激子和缺陷；(2)碳纳米管中的等离子体；(3)有机半导体的降解过程；(4)磁场成像用磁光聚合物；(5)用于给药的纳米颗粒；(6)陨石的组成。对于所有这些项目来说，在亚波长尺度上探测材料的光学响应的能力对于提高材料研究和开发的知识以及探索有益于社会的新应用至关重要。该奖项反映了美国国家科学基金会的法定使命，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。

Non-Technical DescriptionThe resolution of traditional optical microscopes is limited to approximately half the wavelength of light. This Major Research Instrumentation project acquires a state-of-the-art, scanning near-field optical microscope that enables the optical investigation of nanomaterials cooled to liquid-helium temperature and mapping of chemical composition at more than ten times this spatial resolution. The microscope operates by focusing a light source onto a metallized tip and enhancing the local electric field by plasmonic excitation. The microscope detects the backscattered light as a function of position to map the optical properties of the sample. The unique instrument capabilities help to establish the University of Arizona as a regional and national hub for the optical characterization of materials that is broadly accessible to users from throughout the United States. The addition of the microscope provides cutting-edge student training, education, and workforce development opportunities and leads to advances in physics, materials science, photonics, life sciences, and planetary sciences. The instrument is also showcased in an annual workshop in conjunction with the spring Materials Research Society meeting in Phoenix, and used in an annual summer training course on scanning probe microscopy for students and other early-career researchers, many of whom come from underrepresented groups in science and engineering. The scanning near-field optical microscope complements a suite of multiuser systems at the University of Arizona for the characterization of nanomaterials over a large spatial and energy scale.Technical DescriptionThe scanning near-field optical microscope has several unique features such as the ability to reach temperatures less than 10 K, to perform spatially resolved Fourier transform infrared spectroscopy with sub-wavelength resolution, to perform near-field mapping using both visible and near-infrared sources, and to perform tip-enhanced photoluminescence measurements. The microscope supports a broad range of research projects, including: (1) excitons and defects in atomically thin materials; (2) plasmonics in carbon nanotubes; (3) degradation processes in organic semiconductors; (4) magneto-optical polymers for magnetic field imaging; (5) nanoparticles for drug delivery; and (6) the composition of meteorites. For all of these projects, the ability to probe the optical response of the materials at the sub-wavelength scale is essential to advance knowledge for materials research and development, and to explore new applications that benefit the society.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.