Study of the mesoscopic nano-structures by using the scanning near-field Raman spectroscopy

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Most of the condensed matters have the hierarchical structures especially in the structural phase transition. The microscopic atomic arrangements form the mesoscopic structures in the intermediate range. In addition, the higher structures appear from the mesoscopic structures. Therefore, it is necessary to study the mesoscopic structures appeared in the nano-scale region in order to understand the physical property of the condensed mater. To observe the nano-Raman scattering spectra in the mesoscopic structure, a new type of scanning near-field Raman spectroscopic system has been developed by combing scanning atomic force microscopy with micro-Raman scattering spectroscopy.For the observation from the nano-scale region which is smaller than the wavelength of the light, a silicon cantilever with the minute aperture was used both as the illumination nano-scale and the nano-detector of scattered light. We applied for a patent about this technique. To get better performance, the spectroscopic system bas been reconstituted by using the selected optical components such as the lens, miller, filter and so on.Because the mesoscopic structure emerges at its characteristic temperature, the temperature of the sample should be controlled in the wide range. Thus, we have developed the temperature controlled sample-stage which can set in the scanning near-field Raman spectrometer. The sample-stage was required high performance: high temperature stability, low optical loss at the window, including the piezo-scanning system of the cantilever, removing the vibration produced by the vacuum pump and so on.The near-field Raman scattering spectra were successfully observed by using the system developed in the present study. In the next phase, we will attack the phenomena in the mesoscopic structure.