Development of Nanoscale Laser Spectroscopy Based on Photon STM for the Study of Semiconductor Mesoscopic Systems

本课题的目的是通过制作既可在真空中使用又可在低温下使用的光纤探针AFM/SNOM仪器来验证光子扫描近场光学显微镜（Scanning Near-field Optical Microscope，SNOM）的有效性。作为SNOM测量的典型样品，我们采用了在玻璃板上二维自组织的聚苯乙烯颗粒（LATEX）层。1）利用该照明模式测量了LATEX层的透射和发光激发图像。观察到电磁波既可沿沿着层面传播，又可垂直于层面传播，并具有一些较好的传播方向。发现SNOM图像依赖于激光的波长，并期望揭示这种二维周期性材料的光子带效应的一些特性。实验结果表明，在光探针的照射和收集模式下，系统都能获得相同的图像，并讨论了系统的时间反演定理和理论预期。2）在原子力探测中，我们采用了音叉技术，而不受光纤振动传感激光器的杂散光影响。在非局域光学响应理论的框架下，考虑了激发极化的共振和非共振贡献，研究了在一定电子共振条件下，光子能量作用下半导体纳米粒子组装体的SNOM成像.由于组态共振效应，SNOM图像依赖于光纤探针的工作模式，这些结果表明光子扫描隧道显微镜（SNOM）可用于亚微米尺度半导体纳米颗粒的光学测量。

The aim of this project is to ascertain the validity of photon STM (Scanning Near-field Optical Microscope, SNOM) by making AFM/SNOM instruments with cantilever-type optical fiber probe, which can be used in vacuum and also at low temperature. As a typical sample for SNOM measurement, we have adopted the layr of polystirene particles (LATEX) which are self-organized two-dimensionally on a glass plate.1) Transmission and luminescence excitation images of LATEX layrs by the use of the illumination mode have been measured. Electromagnetic waves propagating both along and perpendicular to the layr plane with some preferable propagation directions are observed. The SNOM images are found to be dependent on the wavelength of the laser light and expected to reveal some properties about photonic band effect in this 2D periodic material. The same images are found both in the illumination and the collection modes for the optical probe operation and the time-reversal theorem in this system has been discussed together with theoretical expectation.2) For atomic force detection, we have applied tuning fork technique without suffering from a stray light coming from the laser used for sensing the fiber vibration. Clear images similar to the conventional one are obtained and the quartz detection is found to work at very low temperatures in vacuum.3) SNOM images of assembled semiconductor nanoparticles with photon energy at some electronic resonance condition have been theoretically investigated under the scheme of nonlocal optical response theory by taking into account both the resonant and nonresonant contributions of the induced polarization. The SNOM images are found to be dependent on the operation modes of the fiber probe due to the configuration resonance effect.These results demonstrate the validity of the photon STM (SNOM) for the optical measurement of single or assembled nanoparticles of semiconductors in submicrometer scale.