Time-and Space-Resolved Scanning Probe Microscopy Study and Nano Processing.

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We have developed multifunctional scanning near-field optical microscopy(SNOM) systems that can measure transient absorption and excitation energy transfer, and also examined the nano processing of materials using near-field light.1)Mesoscopic structure of the conductive polymerMesoscopic structures of various conductive polymers were analyzed by time-resolved SNOM. We have found that the structures are strongly dependent on the humidity, and the dynamics of excitation energy transfer in mixed polymer systems have correlated with the phase separation structure of the system.2)The electron transfer to TiO_2Position dependence of the electron transfer dynamics of conductive polymers on TiO_2 thin film was investigated. It was found that electron transfer efficiency on heat-treated TiO_2 thin film was the best one, almost no position dependence on electron transfer dynamics in contrast to the glass surface, suggesting the importance of energy migration and the distribution of the rate con … More stant of electron transfer.3)The excitation energy transferBy combining the local excitation with high NA objective lens and SNOM system, we have constructed the time-resolved microscopy system to measure the length-dependence on the excitation energy transfer.4)Femtosecond transient absorption microspectroscopy and nano processingFemtosecond absorption microspectroscopy system with white-light continuum as a probe pulse was developed for the first time, in which the un-amplified Ti : sapphire laser was introduced into photonic crystal fiber to generate white-light continuum. This system enables us not only to measure very weak absorption change of the order of 10^<-7> under a microscope but also to apply absorption and fluorescence SNOM. Near field nonlinear optical spectroscopy system using cantilever type SNOM is also developed, and heterogeneity inside microcrystals was elucidated. In addition, nano processing of thin microcrystal was demonstrated by near-field light.5)Semiconductor nanoparticle and nanowireWe have synthesized CdS and CdTe nanoparticles and CdTe nanowire. Photophysical properties of these systems were analyzed by picosecond〜femtosecond laser spectroscopy. Organic nanocrystals were also synthesized by reprecipitation and laser ablation methods and characterized by SNOM. Less