Tetsuhiko Nagahara

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We investigated the two-photon-induced photoluminescence properties of single gold nanorods by scanning near-field spectroscopy. The process was found to be initiated by a sequential one-photon absorption for creating a pair of an electron and a hole in the sp and d bands. Photoluminescence is then radiated when the electron near the Fermi surface(More)
We have investigated two-photon-induced photoluminescence images and spectra of single gold nanorods by using an apertured scanning near-field optical microscope. The observed PL spectrum of single gold nanorod can be explained by the radiative recombination of the electron-hole pair near the X and L symmetry points. PL images reveal characteristic features(More)
We have investigated optical properties of single gold nanorods by using an apertured-type scanning near-field optical microscope. Near-field transmission spectrum of single gold nanorod shows several longitudinal surface plasmon resonances. Transmission images observed at these resonance wavelengths show oscillating pattern along the long axis of the(More)
Thin films of chiral porphyrin J-aggregates have been studied by vibrationally and electronically doubly resonant sum frequency generation (SFG) spectroscopy. It was revealed that the chiral supramolecular structures of porphyrin aggregates in solutions were retained in the thin film samples, and their chirality was determined by using chiral vibrational(More)
We fabricated porphyrin thin films on mica surfaces from acidic aqueous solutions of the preorganized H-aggregates of amphiphilic porphyrins by the simple spin-coating method. The morphological and spectroscopic properties of the film were investigated by scanning near-field optical microscopy. The results obtained in this study demonstrate that the(More)
Mesoscopic properties of J-aggregates of water-soluble [tetrakis(4-sulfonatophenyl)porphyrin] and water-insoluble [tetrakis(4-methoxyphenyl)porphyrin and tetraphenylporphyrin] tetraphenylporphyrin derivatives in thin films have been investigated by scanning near-field optical microscopy. From surface topography, the sample films were found to be composed of(More)
A microscopic chromatography has been developed where nanometer-size molecules or particles are separated according to their size by the laser-induced shockwave in a water-filled capillary. As the shockwave passed through the mixture of molecules/particles in solution, they move to the direction of the propagation of the shockwave. The distance from the(More)
We have synthesized double-chain disulfides of adenine with different chain lengths (n = 2, 4, 5, 9, and 10) and studied their self-assembled monolayers (SAM) on gold surface by IR-UV doubly resonant sum frequency generation spectroscopy with the help of DFT calculation. A versatile way to investigate the orientation angle of functional groups of SAMs and(More)
A novel method for compressing a laser pulse, using a combination of transient stimulated Raman scattering and a pump-probe technique, is proposed. The approach does not require a short laser pulse, in contrast to a reported method based on impulsive stimulated Raman scattering. The observed spectrum was sufficiently broad to generate a sub-10 fs pulse. In(More)
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