Development of Variable - Temperature Near-Field Scanning Optical Microscope

设计并制造了一台近场扫描光学显微镜（NSOM），用于研究温度范围为10 ~ 400 K的样品。波长1500至400纳米范围内的光将通过光纤波导引导到位于样品表面上方的直径为20至200纳米的锥形末端。NSOM的分辨率比衍射极限小一个数量级以上，是唯一能够探测尺度远小于1微米的结构的光学技术。NSOM将用于高温约瑟夫森结中电流的空间变化研究。结界面附近的缺陷引起电流的不均匀流动，但缺陷的特征和分布在很大程度上是未知的。第二个项目将研究导电聚合物发光二极管光发射的空间依赖性。NSOM尖端将充当从样品发射的光的局部收集器。将开发一种近场扫描光学显微镜，在远小于普通光衍射极限的尺度上研究空间不均匀性。该显微镜将工作在10k ~ 400k的温度范围内，用于研究高温超导体Josephson结中电流的空间变化，其次，用于研究导电聚合物发光二极管发光的空间变化。

A near-field scanning optical microscope (NSOM) will be designed and constructed to study samples in the temperature range 10 K to 400 K. Light in the wavelength region 1500 to 400 nanometer range will be channeled down a fiber-optic wave guide to a tapered end with an aperture of size 20 to 200 nanometers positioned just above the sample surface. The NSOM is capable of resolution more than an order of magnitude smaller than the diffraction limit and is the only optical technique capable of probing structures with features on a scale much less than 1 micrometer. The NSOM will be employed for the study of spatial variation of the current flow in high-temperature Josephson junctions. Defects near the junction interfaces cause inhomogeneous current flow, but the characteristics and distribution of the defects are largely unknown. A second project will study the spatial dependence of the optical emmission from conducting polymer light-emitting diodes. The NSOM tip will act as a localized collector of light emitted from the sample. A near-field scanning optical microscope will be developed to study spatial imhomogeneities on a scale much less than the diffraction limit of ordinary light. The microscope will operate in the temperature regime 10 K to 400 K and will be used to study the spatial variation of the electrical current in high temperature superconductor Josephson junctions and, secondly, the spatial variation of light emitted from conducting polymer light-emitting diodes.