利用聚碳酸酯模板制备的金纳米棒的表面增强Raman散射效应研究

采用聚碳酸酯模板和电化学沉积法制备基于金纳米棒的Raman场增强衬底, 制备的金纳米棒直径大约36 nm, 长约1 μm, 测试结果显示其共振吸收峰的位置约为540 nm. 比较了谐振和非谐振条件下的场增强情况, 并确定了场增益系数, 结果显示谐振激光激发下的增益比非谐振情况下提高了7.36倍. 本研究相对于前人的工作取得了如下进展: 一是讨论了谐振模式与非谐振模式下的金纳米棒的场增益系数, 利用谐振波长的激光激发金纳米棒, 进一步提高了场增益; 二是消除了聚碳酸酯模板分子的荧光背底, 使其在表面增强 Raman 散射方面的应用进一步变得可行. 关键词： 金纳米棒 表面增强Raman散射 聚碳酸酯模板     

SETUP AND APPLICATION OF SCANNING NEAR-FIELD OPTICAL MICROSCOPY

The research on the setup and application of scanning near-field optical microscopy (SNOM) performed in our laboratory is reviewed in this report. We have constructed a versatile low temperature scanning near-field optical microscope with the capability of near-field imaging and spectroscopy, operating at liquid nitrogen temperature. A special designed coaxial double lens was used to introduce the illumination beam through a 200μm fiber; the detected optical signal was transmitted via a fiber tip to an avalanche photon detector. The performance test shows the stability of the new design. The shear force image and optical image of a standard sample are shown. A system of SNOM working at room temperature and atmosphere was used to characterize semiconductors and bio-molecular samples. It revealed the unique features of semiconductor microdisks in the near-field that is significantly different from that of far-field. The effects of different geographic microstructures on the near-field light distribution of InGaP, GaN, and InGaN multi-quantum-well microdisk were observed.