Total Internal Reflection-Based Extinction Spectroscopy of Single Nanoparticles
Total Internal Reflection-Based Extinction Spectroscopy of Single Nanoparticles
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DOI：
10.1002/anie.201810324
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发表时间：
2019-01-08
影响因子：
16.6
通讯作者：
Wang, Wei
中科院分区：
文献类型：
--
作者：
Li, Meng;Yuan, Tinglian;Wang, Wei
在这里，我们报告了一种反射模式的全内反射显微镜（TIRM）来测量各个介电，等离子体或光吸收纳米粒子的消光光谱，并区分吸收和散射成分的总光输出。这些功能是通过用消逝波照射样品来实现的，消逝波的光路长度与单个纳米颗粒的尺寸相当，从而使反射率变化（Delta I/I-0）显着改善，高达百分之几十。进一步发现，光的散射和吸收分别在单个纳米颗粒的光学图案中促成亮和暗质心，从而允许通过使用适当的图像处理方法从消光光谱中区分散射和吸收组分。此外，TIRM的宽视场特性使得能够在温和的照明下同时对数十个纳米颗粒进行研究。
Herein we report a reflection-mode total internal reflection microscopy (TIRM) to measure the extinction spectrum of individual dielectric, plasmonic, or light-absorbing nanoparticles, and to differentiate absorption and scattering components from the total optical output. These capabilities were enabled via illuminating the sample with evanescent wave of which the lightpath length was comparable with the size of single nanoparticles, leading to a dramatically improved reflectance change (Delta I/I-0) up to tens of percent. It was further found that scattering and absorption of light contributed to bright and dark centroids, respectively, in the optical patterns of single nanoparticles, allowing to distinguish scattering and absorption components from the extinction spectrum by the use of an appropriate image processing method. In addition, wide-field feature of TIRM enabled the studies on tens of nanoparticles simultaneously with gentle illumination.