Hillenbrand R, Knoll B, Keilmann F
Max-Planck-Institut für Biochemie, D-82152 Martinsried, Germany.
J Microsc. 2001 Apr;202(Pt 1):77-83. doi: 10.1046/j.1365-2818.2001.00794.x.
We have enhanced the apertureless scattering-type scanning near-field optical microscope by two improvements which together achieve a recording of the true near field without any height-induced artefact. These are the use of interferometric detection of the scattered light on one hand, and the use of higher-harmonic dither demodulation of the scattered signal on the other. Here we present the basic rationale for these techniques, and give examples measured with two different experiments, one in the infrared (10 microm wavelength), the other in the visible (633 nm). The latter operates in a fully heterodyne mode and displays simultaneous images of optical near-field phase and amplitude, at below 10 nm resolution.
我们通过两项改进提升了无孔径散射型扫描近场光学显微镜，这两项改进共同实现了对真实近场的记录，且不存在任何由高度引起的伪像。一方面是对散射光采用干涉检测，另一方面是对散射信号采用高次谐波抖动解调。在此，我们阐述这些技术的基本原理，并给出两个不同实验的测量示例，一个在红外波段（波长10微米），另一个在可见光波段（633纳米）。后者以全外差模式运行，能以低于10纳米的分辨率同时显示光学近场相位和幅度的图像。
