Publications
ResearcherID : C-5956-2008 (TY, h-index: 24) , AAZ-8749-2021 (RK, h-index: 11)
Google Scholar : TY (h-index: 33), RK (h-index: 11)
2011
Hiroaki Matsui, Wataru Nomura, Takashi Yatsui, Motoichi Ohtsu, Hitoshi Tabata
Optical dynamics of energy-transfer from a CdZnO quantum well to a proximal Ag nanostructure Journal Article
In: Optics Letters, vol. 36, no. 19, pp. 3735–3737, 2011.
Abstract | Links | BibTeX | タグ: Energy-transfer, Plasmon, QW
@article{Matsui:11,
title = {Optical dynamics of energy-transfer from a CdZnO quantum well to a proximal Ag nanostructure},
author = {Hiroaki Matsui and Wataru Nomura and Takashi Yatsui and Motoichi Ohtsu and Hitoshi Tabata},
doi = {10.1364/OL.36.003735},
year = {2011},
date = {2011-10-01},
journal = {Optics Letters},
volume = {36},
number = {19},
pages = {3735--3737},
publisher = {OSA},
abstract = {We studied photoluminescence (PL) and energy-transfer dynamics in a hybrid structure comprising a Cd0.08Zn0.92O quantum well (QW) and an Ag nanostructure. The observed PL quenching was dependent on the electronic states in the QW. Quenching occurred at low temperature where excited carriers recombined radiatively because of excitonic localization, which disappeared with increasing temperature due to delocalization of excitons. Furthermore, nanostructured Ag surfaces produced local surface plasmon (LSP) absorption that was resonant with the PL peak energy of the QW emission. These results indicate that the recombination energy of excitons transfers nonradiatively to induce LSP excitation, which was revealed using time-resolved PL measurements.},
keywords = {Energy-transfer, Plasmon, QW},
pubstate = {published},
tppubtype = {article}
}
We studied photoluminescence (PL) and energy-transfer dynamics in a hybrid structure comprising a Cd0.08Zn0.92O quantum well (QW) and an Ag nanostructure. The observed PL quenching was dependent on the electronic states in the QW. Quenching occurred at low temperature where excited carriers recombined radiatively because of excitonic localization, which disappeared with increasing temperature due to delocalization of excitons. Furthermore, nanostructured Ag surfaces produced local surface plasmon (LSP) absorption that was resonant with the PL peak energy of the QW emission. These results indicate that the recombination energy of excitons transfers nonradiatively to induce LSP excitation, which was revealed using time-resolved PL measurements.
2006
Tadashi Kawazoe, Takashi Yatsui, Motoichi Ohtsu
Nanophotonics using optical near fields Journal Article
In: Journal of Non-Crystalline Solids, vol. 352, no. 23, pp. 2492 - 2495, 2006, ISSN: 0022-3093, (review article).
Abstract | Links | BibTeX | タグ: Nanocrystals, Non-linear optics, QW, Review
@article{KAWAZOE20062492,
title = {Nanophotonics using optical near fields},
author = {Tadashi Kawazoe and Takashi Yatsui and Motoichi Ohtsu},
doi = {10.1016/j.jnoncrysol.2006.03.023},
issn = {0022-3093},
year = {2006},
date = {2006-07-01},
journal = {Journal of Non-Crystalline Solids},
volume = {352},
number = {23},
pages = {2492 - 2495},
abstract = {This paper introduces recent successes in nanophotonics utilizing local electromagnetic interactions between a few nanometric elements (i.e., the optical near-field interaction). The sections of this paper review nanophotonic devices, nanofabrication, and systems for operating nanophotonic devices efficiently. Using CuCl quantum dots, the operations of an optical switch measuring 20-nm in size (i.e., a nanophotonic switch) and a nanometric optical condenser, which attracts optical energy into a 10-nm spot (i.e., an optical nano-fountain), were verified experimentally. The power consumption of these devices is only 1/100000 that of conventional electronic devices. A nanodot coupler fabricated from a linear array of closely spaced metallic nanoparticles has also been introduced for transmitting an optical signal to a nanophotonic device. To increase the optical far- to near-field conversion efficiency for transmission, a surface plasmon polariton (SPP) condenser was fabricated from hemispherical metallic nanoparticles, so that it worked as a ‘phased array’. The SPP can be focused with a spot size as small as 400nm.},
note = {review article},
keywords = {Nanocrystals, Non-linear optics, QW, Review},
pubstate = {published},
tppubtype = {article}
}
This paper introduces recent successes in nanophotonics utilizing local electromagnetic interactions between a few nanometric elements (i.e., the optical near-field interaction). The sections of this paper review nanophotonic devices, nanofabrication, and systems for operating nanophotonic devices efficiently. Using CuCl quantum dots, the operations of an optical switch measuring 20-nm in size (i.e., a nanophotonic switch) and a nanometric optical condenser, which attracts optical energy into a 10-nm spot (i.e., an optical nano-fountain), were verified experimentally. The power consumption of these devices is only 1/100000 that of conventional electronic devices. A nanodot coupler fabricated from a linear array of closely spaced metallic nanoparticles has also been introduced for transmitting an optical signal to a nanophotonic device. To increase the optical far- to near-field conversion efficiency for transmission, a surface plasmon polariton (SPP) condenser was fabricated from hemispherical metallic nanoparticles, so that it worked as a ‘phased array’. The SPP can be focused with a spot size as small as 400nm.
2005
Takashi Yatsui, Motoichi Ohtsu, Jinkyoung Yoo, Sung Jin An, Gyu-Chul Yi
Near-field measurement of spectral anisotropy and optical absorption of isolated ZnO nanorod single-quantum-well structures Journal Article
In: Applied Physics Letters, vol. 87, no. 3, pp. 033101, 2005.
Abstract | Links | BibTeX | タグ: First, Near-field spectroscopy, QW, ZnO
@article{doi:10.1063/1.1990247,
title = {Near-field measurement of spectral anisotropy and optical absorption of isolated ZnO nanorod single-quantum-well structures},
author = {Takashi Yatsui and Motoichi Ohtsu and Jinkyoung Yoo and Sung Jin An and Gyu-Chul Yi},
doi = {10.1063/1.1990247},
year = {2005},
date = {2005-07-01},
urldate = {2005-07-01},
journal = {Applied Physics Letters},
volume = {87},
number = {3},
pages = {033101},
abstract = {We report low-temperature near-field spectroscopy of isolated ZnO∕ZnMgO single-quantum-well structures (SQWs) on the end of ZnO nanorod to define their potential for nanophotonics. First, absorption spectra of isolated ZnO∕ZnMgO nanorod SQWs with the Stokes shift as small as 3meV and very sharp photoluminescent peaks indicate that the nanorod SQWs are of very high optical quality. Furthermore, we performed polarization spectroscopy of isolated ZnO SQWs, and observed valence-band anisotropy of ZnO SQWs in photoluminescence spectra directly. Since the exciton in a quantum structure is an ideal two-level system with long coherence times, our results provide criteria for designing nanophotonic devices.},
keywords = {First, Near-field spectroscopy, QW, ZnO},
pubstate = {published},
tppubtype = {article}
}
We report low-temperature near-field spectroscopy of isolated ZnO∕ZnMgO single-quantum-well structures (SQWs) on the end of ZnO nanorod to define their potential for nanophotonics. First, absorption spectra of isolated ZnO∕ZnMgO nanorod SQWs with the Stokes shift as small as 3meV and very sharp photoluminescent peaks indicate that the nanorod SQWs are of very high optical quality. Furthermore, we performed polarization spectroscopy of isolated ZnO SQWs, and observed valence-band anisotropy of ZnO SQWs in photoluminescence spectra directly. Since the exciton in a quantum structure is an ideal two-level system with long coherence times, our results provide criteria for designing nanophotonic devices.
2004
Takashi Yatsui, Jungshik Lim, Motoichi Ohtsu, Sung Jin An, Gyu-Chul Yi
In: Applied Physics Letters, vol. 85, no. 5, pp. 727-729, 2004.
Abstract | Links | BibTeX | タグ: First, nanorod, Near-field spectroscopy, QW, ZnO
@article{doi:10.1063/1.1776338,
title = {Evaluation of the discrete energy levels of individual ZnO nanorodsingle-quantum-well structures using near-field ultraviolet photoluminescence spectroscopy},
author = {Takashi Yatsui and Jungshik Lim and Motoichi Ohtsu and Sung Jin An and Gyu-Chul Yi},
doi = {10.1063/1.1776338},
year = {2004},
date = {2004-08-01},
urldate = {2004-08-01},
journal = {Applied Physics Letters},
volume = {85},
number = {5},
pages = {727-729},
abstract = {Spatially and spectrally resolved photoluminescence imaging of individual ZnO∕ZnMgO nanorod single-quantum-well structures (SQWs) with a spatial resolution of 55nm was performed using the optical near-field technique with a metallized UV fiber probe. Using excitation power density-dependent photoluminescence spectra of a ZnO∕ZnMgO SQW nanorod, we observed the discrete energy levels in a ZnO quantum-well layer.},
keywords = {First, nanorod, Near-field spectroscopy, QW, ZnO},
pubstate = {published},
tppubtype = {article}
}
Spatially and spectrally resolved photoluminescence imaging of individual ZnO∕ZnMgO nanorod single-quantum-well structures (SQWs) with a spatial resolution of 55nm was performed using the optical near-field technique with a metallized UV fiber probe. Using excitation power density-dependent photoluminescence spectra of a ZnO∕ZnMgO SQW nanorod, we observed the discrete energy levels in a ZnO quantum-well layer.