Development of time-resolved near-field fluorescence spectroscopy and optical control of photodynamics in mesoscopic domains

该项目的目的是开发一个时间分辨率为皮秒、空间分辨率为几十nm的近场时间分辨荧光光谱系统，并探索在介观领域控制光化学反应的可能性。利用该系统，介观区域的光化学动力学特性可以被解释为空间位置的函数。皮秒逝去波诱导荧光光谱系统。研制了以逝去波为激发源的单光子定时系统。该系统采用蓝宝石等全内反射元件，具有-30ps的时间分辨率和-20 nm的深度分辨率。通过近红外激光的消逝波，可逆地实现了水溶性聚合物在固/水界面层中的相变，这表明光学控制界面层中的物理性质是可能的。皮秒扫描近场光学麦克风…更多镜片(SNOM)。将孔径为50-100 nm的锥形镀铝光纤与皮秒锁模的Nd：YLF激光器耦合，并用-nm分辨率的压电式换能器进行扫描。通过倒置显微镜和单光子计时相结合的方法，检测到了透射模式下的诱导荧光和散射强度，其时间分辨率为20-30ps，空间分辨率为200-300 nm。介观领域中的光动力学。用皮秒近场光学显微镜研究了粒径为100-300 nm的聚合物胶乳粒子的荧光动力学随位置的变化。结果发现，不同颗粒的染料荧光衰减几乎相同，而染料在玻璃片上的位置依赖性很强。综上所述，我们建立了一个时间分辨的近场荧光光谱系统，它使我们能够研究介观区域内的皮秒动力学以及控制光化学反应。较少

The purpose of the project is to develop a near-field time-resolved fluorescence spectroscopic system with a picosecond temporal and a few tens of nm-spatial resolutions and to investigate a possibility of the control of photochemical reactions in mesoscopic domains. Using this system, photochemical dynamics characteristic in mesoscopic domains can be elucidated as a function of spatial position.1. Picosecond evanescent wave-induced fluorescence spectroscopic system. Single-photon timing system with a excitation of evanescent wave was developed. This system has a temporal resolution of -30 ps and a depth resolution of -20 nm by using a total internal reflection element such as a sapphire. Phase transition of a water-soluble polymer in the solid/aqueous solution interface layr has been achieved reversibly by an evanescent wave of near IR laser, indicating the possibility of the optical control of the physical properties in the interface layr.2. Picosecond scanning near field optical mic … More roscopy (SNOM). A tapered aluminized fiber with a 50-100 nm aperture was coupled with a picosecond mode-locked Nd : YLF laser and scanned by piezoelectric transducers with -nm resoluton. The induced fluorescence and scattered intensity in a transmission mode were detected by a combination of a inverted microscope and a single-photon timing method, which resulted in a temporal resolution of 20-30 ps and a spatial resoluton of 200-300 nm.3. Photodynamics in mesoscopic domains. Fluorescence dynamics of polymer latex particles with well defined seizes (100-300nm diameter) were investigated by picosecond SNOM as a function of position. It was found that the fluorescence decays are almost the same irrespective of particles, whereas position dependence was strongly observed in dye adsorbates on glass plates.In conclusion, we have developed a time-resolved near-field fluorescence spectroscopy system, which allows us to investigate the picosecond dynamics in mesoscopic domains as well as to control the photochemical reactions. Less