古川 裕介
| 基盤理工学専攻 | 特任准教授 |
研究者情報
経歴
研究活動情報
論文
- Vacuum ultraviolet luminescence from a micro-pulling-down method grown Nd3+:(La-0.9,Ba-0.1)F-2.9
Marilou Cadatal; Yusuke Furukawa; Shingo Ono; Minh Pham; Elmer Estacio; Tomoharu Nakazato; Toshihiko Shimizu; Nobuhiko Sarukura; Kentaro Fukuda; Toshihisa Suyama; Akira Yoshikawa; Fumio Saito
JOURNAL OF LUMINESCENCE, ELSEVIER SCIENCE BV, 129巻, 12号, 掲載ページ 1629-1631, 出版日 2020年12月09日, 査読付, Vacuum ultraviolet (VUV) luminescence from a Nd3+(La1-x,Ba-x)F3-x (x = 0 1) and a Nd3+. LaF3 single crystal grown by the micro-pulling-down method modified for fluoride crystal growth is discussed Emission resulting from excitation with 157 nm pulses of a F-2 laser and by 290 nm femtosecond Pulses of a Ti sapphire laser show that the luminescence spectral and temporal characteristics are similar for both excitation cases and that they have good prospects as a VUV laser material (C) 2009 Elsevier B V All rights reserved
研究論文（学術雑誌）, 英語 - Nd3+:(La1-xBax)F3-x grown by micro-pulling down method as vacuum ultraviolet scintillator and potential laser material
Marilou Cadatal; Young-Seok Seo; Shingo Ono; Yusuke Furukawa; Elmer Estacio; Hidetoshi Murakami; Yasushi Fujimoto; Nobuhiko Sarukura; Masahiro Nakatsuka; Toshihisa Suyama; Kentaro Fukuda; Rayko Simura; Akira Yoshikawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, INST PURE APPLIED PHYSICS, 46巻, 36-40号, 掲載ページ L985-L987, 出版日 2020年10月07日, 査読付, Nd3+:(La1-xBax)F3-x (x = 0.1) efficiently grown by the micro-pulling down method is explored. Transparency down to 164 nm and broad fluorescence centered at 175 nm make it a novel vacuum ultraviolet scintillator and a potential tunable laser material with the capability of short pulse amplification.
研究論文（学術雑誌）, 英語 - Laser quality Ce3+: LiCaAlF6 grown by micro-pulling-down method
Minh H. Pham; Marilou M. Cadatal; Toshihiro Tatsumi; Ayumi Saiki; Yusuke Furukawa; Tomoharu Nakazato; Elmer Estacio; Nobuhiko Sarukura; Toshihisa Suyama; Kentaro Fukuda; Kyoung Jin Kim; Akira Yoshikawa; Fumio Saito
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOC APPLIED PHYSICS, 47巻, 7号, 掲載ページ 5605-5607, 出版日 2020年07月08日, 査読付, We describe the successful growth of a laser quality Ce3+:LiCaAlF6 crystal using the micro-pulling down method. The crystal is grown using, less than one gram of raw material and a pulling rate of 0.1 mm/min. Ultraviolet laser emission at 290 nm with 23% slope efficiency and 1 mJ pulse energy is demonstrated from a Brewster-cut crystal, which is 30 mm in length and 2 mm in diameter. The flexibility and lower cost of this growth technique will markedly reduce the cost of growing laser grade crystals.
研究論文（学術雑誌）, 英語 - Nd3+:LaF3 as a Step-Wise Excited Scintillator for Femtosecond Ultraviolet Pulses
Tomoharu Nakazato; Marilou Cadatal-Raduban; Kohei Yamanoi; Misuki Tsuboi; Yusuke Furukawa; Minh Pham; Elmer Estacio; Toshihiko Shimizu; Nobuhiko Sarukura; Kentaro Fukuda; Toshihisa Suyama; Takayuki Yanagida; Yuui Yokota; Akira Yoshikawa; Fumio Saito
IEEE TRANSACTIONS ON NUCLEAR SCIENCE, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 57巻, 3号, 掲載ページ 1208-1210, 出版日 2020年06月10日, 査読付, Vacuum ultraviolet fluorescence from Czochralski method-grown Nd3+:LaF3 excited by 290 nm femtosecond pulses from a Ti:sapphire laser is reported. Peak emission at 175 nm with 7 ns lifetime is observed. This decay time would be one of the fastest among solid-state, inorganic scintillators. Laser emission in the VUV region may also be achievable by pumping with existing ultraviolet solid-state lasers.
研究論文（学術雑誌）, 英語 - Multi-photon Dissociative Ionization of D-2 Probed by a-Few-Pulse Attosecond Pulse Train
Tomoya Okino; Yusuke Furukawa; Yasuo Nabekawa; Katsumi Midorikawa
2017 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC), IEEE, 出版日 2017年
研究論文（国際会議プロシーディングス）, 英語 - Sub-10-fs control of dissociation pathways in the hydrogen molecular ion with a few-pulse attosecond pulse train
Yasuo Nabekawa; Yusuke Furukawa; Tomoya Okino; A. Amani Eilanlou; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
NATURE COMMUNICATIONS, NATURE PUBLISHING GROUP, 7巻, 掲載ページ 12835, 出版日 2016年09月, 査読付, The control of the electronic states of a hydrogen molecular ion by photoexcitation is considerably difficult because it requires multiple sub-10 fs light pulses in the extreme ultraviolet (XUV) wavelength region with a sufficiently high intensity. Here, we demonstrate the control of the dissociation pathway originating from the 2p sigma(u) electronic state against that originating from the 2p pi(u) electronic state in a hydrogen molecular ion by using a pair of attosecond pulse trains in the XUV wavelength region with a train-envelope duration of similar to 4 fs. The switching time from the peak to the valley in the oscillation caused by the vibrational wavepacket motion in the 1s sigma(g) ground electronic state is only 8 fs. This result can be classified as the fastest control, to the best of our knowledge, of a molecular reaction in the simplest molecule on the basis of the XUV-pump and XUV-probe scheme.
研究論文（学術雑誌）, 英語 - Observation of attosecond quantum wavepackets in molecules
T. Okino; Y. Nabekawa; Y. Furukawa; K. Midorikawa
2015 11th Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2015, Institute of Electrical and Electronics Engineers Inc., 1巻, 出版日 2016年01月07日, 査読付, Attosecond Fourier transform spectroscopy with attosecond pulse trains is implemented for observing ultrafast quantum wavepacket dynamics in diatomic molecules. Coupled nuclear-electron motions in the molecules are investigated with an attosecond-pump and attosecond probe method.
研究論文（国際会議プロシーディングス）, 英語 - Settling time of a vibrational wavepacket in ionization
Yasuo Nabekawa; Yusuke Furukawa; Tomoya Okino; A. Amani Eilanlou; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
NATURE COMMUNICATIONS, NATURE PUBLISHING GROUP, 6巻, 8197号, 掲載ページ 1-6, 出版日 2015年09月, 査読付, The vibrational wavepacket of a diatomic molecular ion at the time of ionization is usually considered to be generated on the basis of the Franck-Condon principle. According to this principle, the amplitude of each vibrational wavefunction in the wavepacket is given by the overlap integral between each vibrational wavefunction and the ground vibrational wavefunction in the neutral molecule, and hence, the amplitude should be a real number, or equivalently, a complex number the phase of which is equal to zero. Here we report the observation of a non-trivial phase modulation of the amplitudes of vibrational wavefunctions in a wavepacket generated in the ground electronic state of a H-2(+) molecular ion at the time of ionization. The phase modulation results in a group delay of the specific vibrational states of order 1 fs, which can be regarded as the settling time required to compose the initial vibrational wavepacket.
研究論文（学術雑誌）, 英語 - Direct observation of an attosecond electron wave packet in a nitrogen molecule
Tomoya Okino; Yusuke Furukawa; Yasuo Nabekawa; Shungo Miyabe; A. Amani Eilanlou; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
SCIENCE ADVANCES, AMER ASSOC ADVANCEMENT SCIENCE, 1巻, 8号, 掲載ページ 1-7, 出版日 2015年09月, 査読付, Capturing electron motion in a molecule is the basis of understanding or steering chemical reactions. Nonlinear Fourier transform spectroscopy using an attosecond-pump/attosecond-probe technique is used to observe an attosecond electron wave packet in a nitrogen molecule in real time. The 500-as electronic motion between two bound electronic states in a nitrogen molecule is captured by measuring the fragment ions with the same kinetic energy generated in sequential two-photon dissociative ionization processes. The temporal evolution of electronic coherence originating from various electronic states is visualized via the fragment ions appearing after irradiation of the probe pulse. This observation of an attosecond molecular electron wave packet is a critical step in understanding coupled nuclear and electron motion in polyatomic and biological molecules to explore attochemistry.
研究論文（学術雑誌）, 英語 - Frequency-resolved optical gating technique for retrieving the amplitude of a vibrational wavepacket
Yasuo Nabekawa; Yusuke Furukawa; Tomoya Okino; A. Amani Eilanlou; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
SCIENTIFIC REPORTS, NATURE PUBLISHING GROUP, 5巻, 11366号, 掲載ページ 1-14, 出版日 2015年06月, 査読付, We propose a novel method to determine the complex amplitude of each eigenfunction composing a vibrational wavepacket of H-2(+)/D-2(+) molecular ions evolving with a similar to 10 fs time scale. We find that the two-dimensional spectrogram of the kinetic energy release (KER) of H+/D+ fragments plotted against the time delay of the probe pulse is equivalent to the spectrogram used in the frequency-resolved optical gating (FROG) technique to retrieve the complex amplitude of an ultrashort optical pulse. By adapting the FROG algorithm to the delay-KER spectrogram of the vibrational wavepacket, we have successfully reconstructed the complex amplitude. The deterioration in retrieval accuracy caused by the bandpass filter required to process actual experimental data is also discussed.
研究論文（学術雑誌）, 英語 - Simultaneous Observation of Vibrational Wavepackets of Nitrogen Molecule in Neutral and Singly-Charged Manifolds
T. Okino; Y. Furukawa; A. Amani Eilanlou; Y. Nabekawa; E. J. Takahashi; K. Yamanouchi; K. Midorikawa
ULTRAFAST PHENOMENA XIX, SPRINGER-VERLAG BERLIN, 162巻, 掲載ページ 32-35, 出版日 2015年, 査読付, Vibrational wavepackets of nitrogen molecule were created by attosecond pulse train and their time-evolutions were also probed by attosecond pulse train. Vibrational wavepackets are launched both in neutral electronic states and singly-charged electronic states of nitrogen molecule. The created vibrational wavepackets were excited to the dissociative states and detected as a momentum image of fragment ion using a velocity map momentum imaging ion spectrometer. The fast vibrational wavepackets (T-vib = 15 - 20 fs) were ascribed to the vibrational wavepackets generated in the singly-charged electronic states. The slow vibrational wavepackets T-vib = 50 - 80 fs were ascribed to the vibrational wavepackets generated in the weakly-bounded neutral electronic states. The co-existence of several vibrational wavepackets indicates the possibility to launch the electron wavepacket between these electronic states.
研究論文（国際会議プロシーディングス）, 英語 - Attosecond Frequency Resolved Momentum Imaging of Two-Photon Dissociative Ionization Dynamics of Nitrogen Molecule
T. Okino; Y. Furukawa; A. Amani Eilanlou; Y. Nabekawa; E. J. Takahashi; K. Yamanouchi; K. Midorikawa
ULTRAFAST PHENOMENA XIX, SPRINGER-VERLAG BERLIN, 162巻, 掲載ページ 24-27, 出版日 2015年, 査読付, Two-photon dissociative ionization processes of nitrogen molecule are investigated with attosecond nonlinear Fourier transformation spectroscopy. Nonlinear absorption spectrum of nitrogen molecule are extracted by measuring interferometric autocorrelation of a-few-pulse attosecond pulse train using nonsequential two-photon processes of nitrogen molecule. The frequency resolved momentum images (FRMI) are reconstructed from the delay dependent momentum images of fragment ion N+ and the resultant FRMIs show the attosecond nonlinear response of nitrogen molecule.
研究論文（国際会議プロシーディングス）, 英語 - High-Order Harmonics Fourier Transform Spectroscopy of Two-Photon Dissociative Ionization of Hydrogen Molecules
Yusuke Furukawa; T. Okino; Y. Nabekawa; A. Amani Eilanlou; E. J. Takahashi; K. Yamanouchi; K. Midorikawa
ULTRAFAST PHENOMENA XIX, SPRINGER-VERLAG BERLIN, 162巻, 掲載ページ 28-31, 出版日 2015年, 査読付, High-order harmonic generation provides us a coherent femtosecond pulse in a vacuum ultraviolet wavelength region. We have investigated the two-photon dissociative ionization of deuterium molecules by Fourier transform spectroscopy with a high-order harmonic generation pulse. We measured the delay-dependent kinetic energy distribution of the deuteron fragments resulting from the dissociative ionization by scanning the delay between the two replicas of the high-order harmonic generation pulse. From the Fourier transform analysis, we successfully distinguished the harmonic order, which induced the photodissociation and provided the specific kinetic energy to the fragments via the repulsive electronic excited state.
研究論文（国際会議プロシーディングス）, 英語 - Intense Attosecond Pulses for Probing Ultrafast Molecular Dynamics
E. J. Takahashi; P. Lan; T. Okino; Y. Furukawa; Y. Nabekawa; K. Yamanouchi; K. Midorikawa
ULTRAFAST PHENOMENA XIX, SPRINGER-VERLAG BERLIN, 162巻, 掲載ページ 16-19, 出版日 2015年, 査読付, Recent developments of high energy high-harmonic beam line pumped by 100 Hz 12 fs Ti:sapphire laser for attosecond nonlinear Fourier transformation spectroscopy and multi-gigawatt isolated attosecond pulses by infrared two-color laser field synthesis are reported.
研究論文（国際会議プロシーディングス）, 英語 - Probing atomic and molecular processes by intense attosecond pulses
Y. Nabekawa; T. Okino; Y. Furukawa; Katsumi Midorikawa
Optics InfoBase Conference Papers, Optical Society of America (OSA), 出版日 2014年10月14日, Two-photon dissociative ionization processes of simple molecules are investigated by attosecond nonlinear Fourier transformation spectroscopy. The frequency resolved momentum images of the fragment ions reveal ultrafast dissociative ionization dynamics of molecules. © OSA 2014.
研究論文（国際会議プロシーディングス）, 英語 - Observation of vibrational wavepacket evolution of H2+ by time-resolved spectroscopy of HHG pulses
Yusuke Furukawa; Tomoya Okino; A. Amani Eilanlou; Yasuo Nabekawa; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
JSAP-OSA Joint Symposia, JSAP 2014, Optical Society of America, 出版日 2014年09月01日
研究論文（国際会議プロシーディングス）, 英語 - Vibrational wavepacket reconstruction with frequency-resolved optical gating technique
Yasuo Nabekawa; Yusuke Furukawa; Tomoya Okino; A. Amani Eilanlou; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
JSAP-OSA Joint Symposia, JSAP 2014, Optical Society of America (OSA), 出版日 2014年09月01日
研究論文（国際会議プロシーディングス）, 英語 - Tracking vibrational wavepackets of nitrogen molecules by XUV-pump XUV-probe with momentum imaging
Tomoya Okino; Yusuke Furukawa; A. Amani Eilanlou; Yasuo Nabekawa; Eiji J Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
JSAP-OSA Joint Symposia, JSAP 2014, Optical Society of America (OSA), 出版日 2014年09月01日
研究論文（国際会議プロシーディングス）, 英語 - Frequency-resolved optical gating technique to retrieve the amplitude of a vibrational wavepacket of H+2
Y. Nabekawa; Y. Furukawa; T. Okino; A. Amani Eilanlou; E. J. Takahashi; K. Yamanouchi; K. Midorikawa
Optics InfoBase Conference Papers, OSA - The Optical Society, 出版日 2014年07月21日
研究論文（国際会議プロシーディングス）, 英語 - Nonlinear Fourier transformation spectroscopy of small molecules with intense attosecond pulse train
T. Okino; Y. Furukawa; T. Shimizu; Y. Nabekawa; K. Yamanouchi; K. Midorikawa
JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, IOP PUBLISHING LTD, 47巻, 12号, 掲載ページ 124007, 出版日 2014年06月, 査読付, We have developed an attosecond nonlinear molecular spectroscopic method called nonlinear Fourier transformation spectroscopy (NFTS) that uses an intense attosecond pulse train (APT) to induce multiphoton ionization processes. In the NFTS method, in addition to characterization of the temporal profile of attosecond pulses, the nonlinear molecular responses are encoded in the interferometric autocorrelation traces depending on the molecular species, their fragment ions and their kinetic energy distributions. The principle and applicability of the NFTS method are described in this paper along with the numerical simulations. The method is applied to diatomic molecules (N-2, D-2 and O-2) and polyatomic molecules (CO2, CH4 and SF6). Our results highlight the fact that nonlinear spectroscopic information of molecules in the short wavelength region can be obtained through the irradiation of intense APT by taking advantage of the broad spectral bandwidth of attosecond pulses. The development of the nonlinear spectroscopic method in attoseconds is expected to pave the way to investigate the ultrafast intramolecular electron motion such as ultrafast charge migration and electron correlation.
研究論文（学術雑誌）, 英語 - Observation of attosecond electronwavepacket of nitrogen molecules by XUV pump-probe with nonlinear fourier transformation spectroscopy
Tomoya Okino; Yusuke Furukawa; A. Amani Eilanlou; Yasuo Nabekawa; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
Optics InfoBase Conference Papers, Optical Society of America (OSA), 出版日 2014年, Multiple electronic states of nitrogen molecules are coherently excited by sub-5 fs harmonics. The generated electron wavepackets between neutral electronic states and singly-charged electronic states are probed by sub-5 fs harmonics by detecting fragment ions. © 2014 OSA.
研究論文（国際会議プロシーディングス）, 英語 - Attosecond frequency resolved momentum imaging of two-photon dissociative ionization dynamics of nitrogen molecule
Tomoya Okino; Yusuke Furukawa; A. Amani Eilanlou; Yasuo Nabekawa; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
Optics InfoBase Conference Papers, Optical Society of America (OSA), 出版日 2014年, Two-photon dissociative ionization processes of nitrogen molecule are investigated with attosecond nonlinear Fourier transformation spectroscopy. The frequency resolved momentum images extracted from delay dependent momentum images showed attosecond nonlinear response of nitrogen molecule. Ultrafast Phenomena 2014 © 2014 OSA.
研究論文（国際会議プロシーディングス）, 英語 - Probing ultrafast molecular dynamics with intense attosecond pulses
T. Okino; E. J. Takahashi; Y. Furukawa; Y. Nabekawa; K. Midorikawa
Optics InfoBase Conference Papers, Optical Society of America (OSA), 出版日 2014年, Recent results on a new attosecond spectroscopic method called as nonlinear Fourier transform spectroscopy using attosecond pulse train and generation of multi-gigawatt isolated attosecond pulses by the infrared two-color laser field synthesis are reported. Ultrafast Phenomena 2014 © 2014 OSA.
研究論文（国際会議プロシーディングス）, 英語 - High-order harmonics fourier transform spectroscopy of two-photon dissociative ionization of hydrogen molecules
Yusuke Furukawa; Tomoya Okino; Yasuo Nabekawa; A. Amani Eilanlou; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
Optics InfoBase Conference Papers, Optical Society of America (OSA), 出版日 2014年, We have investigated two-photon dissociative ionization processes induced by highorder harmonic generation pulses with Fourier transform spectroscopy. Delay-dependent kinetic energy distribution of fragment ions reveals dissociative ionization dynamics of hydrogen molecules. © 2014 OSA.
研究論文（国際会議プロシーディングス）, 英語 - Simultaneous observation of vibrational wavepackets of nitrogen molecule in neutral and singly-charged manifolds
Tomoya Okino; Yusuke Furukawa; A. Amani Eilanlou; Yasuo Nabekawa; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
Optics InfoBase Conference Papers, Optical Society of America (OSA), 出版日 2014年, Vibrational wavepackets are launched at neutral and single-charged electronic excited states of nitrogen molecule by sub-10 fs high harmonics. The evolution of vibrational wavepackets are tracked by sub-10 fs high harmonics. © 2014 OSA.
研究論文（国際会議プロシーディングス）, 英語 - Observation of vibrational wave-packet dynamics in D+ 2 using high-order harmonic pulses
Yusuke Furukawa; Yasuo Nabekawa; Katsumi Midorikawa
Springer Series in Chemical Physics, Springer New York LLC, 106巻, 掲載ページ 33-47, 出版日 2014年, High-order harmonic generation is a unique phenomenon to provide coherent ultrashort light source ranging to the extreme ultraviolet region. In recent years, ultrashort high-harmonic pulses have been used to study ultrafast dynamics in atoms and molecules. We present the pump-probe experimental results on the observation of the vibrational wave-packet dynamics in D+2 utilizing the high-order harmonic laser pulses of a sub-15 fs Ti:sapphire laser pulse. We launch the wavepacket of D+2 by using a sub-10 fs extreme ultraviolet high-harmonic pump pulse, and observe its evolution by using the split harmonic probe pulse, whose wavelength ranges from near infrared to vacuum ultraviolet. This pump-probe scheme can provide us with a powerful experimental tool for investigating a variety of wave packets evolving with a time scale of ∼20 fs.
研究論文（学術雑誌）, 英語 - Nonlinear Fourier-transform spectroscopy revealing wave-packet dynamics of D-2(+) with multicolor harmonic field
Yasuo Nabekawa; Yusuke Furukawa; Tomoya Okino; A. Amani Eilanlou; Kaoru Yamanouchi; Katsumi Midorikawa
XXVIII INTERNATIONAL CONFERENCE ON PHOTONIC, ELECTRONIC AND ATOMIC COLLISIONS (ICPEAC), IOP PUBLISHING LTD, 488巻, 出版日 2014年, We report on a series of studies concerning D, molecules irradiated by high-harmonic pulses generated from intense lemtosecond laser pulses. The kinetic energy (RE) spectrum of dissociated D+ ion fragments with a scanning delay between two replica harmonic pulses exhibits specific characteristics that are completely different from a conventional interferometric autocorrelation signal. We have successfully determined and separated three distinct ionization/dissociation processes by analyzing KE-resolved interferometric fringes by Fourier transform. We call this method for analyzing the KE spectrum of ion fragments "nonlinear Fourier-transform spectroscopy (NETS)." NFTS provides us molecular information in stationary states because it is intrinsically a frequency domain analysis. Nevertheless, we have resolved the real-time evolution of the vibrational wave packet of D+ ions with a period of 22 fs by shortening the pulse duration of the fundamental laser pulse to 12 fs and extending the scanning delay range of two harmonic pulses to 150 fs. The probing process of the wavepacket can be described as a model with one-photon absorption of a multicolor harmonic field. We discuss a possible method of reconstructing the phase and magnitude of the wavepacket from the measured delay-KE spectrogram.
研究論文（国際会議プロシーディングス）, 英語 - Interferometry of an attosecond pulse train generated from Xe gas target
Yasuo Nabekawa; Toshihiko Shimizu; Yusuke Furukawa; Eiji J. Takahashi; Katsumi Midorikawa
CHEMICAL PHYSICS, 414巻, 掲載ページ 20-25, 出版日 2013年03月12日, 査読付
研究論文（学術雑誌）, 英語 - Time-resolved Measurement of Vibrational Wave-Packet Dynamics of H-2(+) Using Multicolor Probe Pulses
Yusuke Furukawa; Tomoya Okino; Yasuo Nabekawa; A. Amani Eilanlou; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE AND INTERNATIONAL QUANTUM ELECTRONICS CONFERENCE (CLEO EUROPE/IQEC), IEEE, 出版日 2013年
研究論文（国際会議プロシーディングス）, 英語 - Attosecond Control of Fragment Ion Angular Distribution of N-2 by a Few Attosecond Pulses
Tomoya Okino; Yusuke Furukawa; A. Amani Eilanlou; Yasuo Nabekawa; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS PACIFIC RIM (CLEO-PR), IEEE, 出版日 2013年, Interferometric autocorrelation of a few-pulse attosecond pulse was measured with single-shot velocity map imaging ion spectrometer using two-photon dissociative ionization process of N-2 and the variation of angular distribution of N+ is controlled within 200 attoseconds.
研究論文（国際会議プロシーディングス）, 英語 - Dissociative Ionization Dynamics of Nitrogen Molecule with Interferometric Autocorrelation of a-few-pulse Attosecond Pulse Train
Tomoya Okino; Yusuke Furukawa; A. Amani Eilanlou; Yasuo Nabekawa; Eiji J. Takahashi; Kaoru Yamanouchi; Katsumi Midorikawa
2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), IEEE, 出版日 2013年, 査読付, We found a significant difference between the interferometric fringes on the intensity-autocorrelation and those on anisotropy-autocorrelation of an atttosecond pulse train. This result can discriminate multiple two-photon processes ionizing a nitrogen molecule. (C) 2013 Optical Society of America
研究論文（国際会議プロシーディングス）, 英語 - Vibrational Wave-Packet Evolution of Hydrogen Molecular Ions Studied by the Pump-Probe Spectroscopy Using Harmonic Pulses
Y. Furukawa; T. Okino; Y. Nabekawa; A. Amani Eilanlou; E. J. Takahashi; K. Yamanouchi; K. Midorikawa
2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS PACIFIC RIM (CLEO-PR), IEEE, 出版日 2013年, 査読付, We have investigated the vibrational wave-packet dynamics of hydrogen molecular ions by the pump-probe measurement using sub-10-fs harmonic pulses. The wave-packet evolution is observed in the time-dependent fragment kinetic energy distribution.
研究論文（国際会議プロシーディングス）, 英語 - Optical properties of hydrothermal-method-grown ZnO crystal as EUV laser diagnostics material
Yamanoi Kohei; Shimizu Toshihiko; Furukawa Yusuke; Cadatal-Raduban Marilou; Nakazato Tomoharu; Sakai Kohei; Tsuboi Mizuki; Nishi Ryosuke; Sarukura Nobuhiko; Tanaka Momoko; Nishikino Masaharu; Yamatani Hiroshi; Nagashima Keisuke; Kimura Toyoaki; Fukuda Tsuguo; Nagasono Mitsuru; Togashi Tadashi; Higashiya Atsushi; Yabashi Makina; Ishikawa Tetsuya; Ohashi Haruhiko; Kimura Hiroaki
Journal of Crystal Growth, 362巻, 掲載ページ 264-267, 出版日 2013年, 査読付 - Resolving vibrational wave-packet dynamics of D-2(+) using multicolor probe pulses
Yusuke Furukawa; Yasuo Nabekawa; Tomoya Okino; A. Amani Eilanlou; Eiji J. Takahashi; Pengfei Lan; Kenichi L. Ishikawa; Takeshi Sato; Kaoru Yamanouchi; Katsumi Midorikawa
OPTICS LETTERS, OPTICAL SOC AMER, 37巻, 14号, 掲載ページ 2922-2924, 出版日 2012年07月, 査読付, We demonstrate the generation and real-time observation of the vibrational wave packet of D-2(+) by using a sub-10-fs extreme UV high-harmonic pump pulse and a three-color probe laser pulse whose wavelength ranges from near-IR to vacuum UV. This multicolor pump-probe scheme can provide us with a powerful experimental tool for investigating a variety of wave packets evolving with a time scale of similar to 20 fs. (C) 2012 Optical Society of America
研究論文（学術雑誌）, 英語 - Material Survey for a Novel Beam Splitter Separating High-Order Harmonics from High-Average-Power Fundamental Pulses
Yosuke Kojima; A. Amani Eilanlou; Yusuke Furukawa; Yasuo Nabekawa; Eiji J. Takahashi; Fumihiko Kannari; Katsumi Midorikawa
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOC APPLIED PHYSICS, 51巻, 6号, 掲載ページ B118-B121, 出版日 2012年06月, 査読付, We have investigated novel beam splitter (BS) materials to relax thermal issues under irradiation of a high-average-power visible and near infrared (VIS-NIR) laser beam. The material should efficiently reflect a high-order harmonic beam in the extreme ultraviolet (XUV) spectral region and transmit a VIS-NIR fundamental laser beam at a Brewster incidence for the latter beam. We have investigated optical and thermo-mechanical properties of crystalline silicon carbide (SiC), diamond, and rutile since they exhibit high transparency and high index of refraction for a VIS-NIR light. We also address thermal issues of conventional opaque BS materials by measuring their thermal distortion. We have shown that crystalline SiC is the most promising candidate among the other materials because of a high reflectivity for XUV light, as well as an ignorable thermal distortion. The surface flatness of a crystalline SiC plate must be improved to realize an applicable BS in the XUV spectral region. (c) 2012 The Japan Society of Applied Physics
研究論文（学術雑誌）, 英語 - Resolving ultrafast wave-packet dynamics of D2+ using multiple harmonic pulses of Ti: Sapphire laser
Y. Furukawa; Y. Nabekawa; P. Lan; E. J. Takahashi; T. Okino; K. Yamanouchi; K. Midorikawa
Optics InfoBase Conference Papers, Optical Society of America (OSA), 出版日 2012年, We have resolved the vibrational wave-packet dynamics of D2+ with a period of ~20-fs generated with sub-10 fs XUV harmonic field. The real-time evolution is probed with the sub-10 fs VUV and DUV harmonic fields. © OSA 2012.
研究論文（国際会議プロシーディングス）, 英語 - XUV interferometry of attosecond pulses
Yasuo Nabekawa; Eiji J. Takahashi; Yusuke Furukawa; Tomoya Okino; Kaoru Yamanouchi; Katsumi Midorikawa
Springer Proceedings in Physics, Springer Science and Business Media, LLC, 125巻, 掲載ページ 127-135, 出版日 2012年, 査読付, We demonstrate the interferometry and Fourier analysis of the attosecond pulse train (APT), which is formed with the Fourier synthesis of multiple highorder harmonic fields in the XUV wavelength region. The ion yield originating from nonlinear interaction of the APT with the nitrogenmolecule exhibits the interference fringes of the XUV harmonic fields on the pulse envelope of the APT in the interferometric autocorrelation (IAC) measurement. We have resolved the kinetic energy spectrum in three distinct regions in accordance with the characteristic of the fringe frequency, although the detailed ionization/dissossiation process is not clear. Another example of the IAC trace obtained from the deuterium ion dose not show the pulse envelope of the APT, while we can clearly observe the interference fringes of low order harmonic field, instead. We have determined the distinct sequential processes of ionization followed by dissociation with Fourier analysis of these fringes. The available wavelength resolution of the measurement device for the IAC, which we call "attocorrelator," has been also demonstrated with the linear interferometry. © Springer-Verlag Berlin Heidelberg 2012.
研究論文（国際会議プロシーディングス）, 英語 - Resolving Ultrafast Wave-packet Dynamics of D-2(+) Using Multiple Harmonic Pulses of Ti:sapphire laser
Y. Furukawa; Y. Nabekawa; P. Lan; E. J. Takahashi; T. Okino; K. Yamanouchi; K. Midorikawa
2012 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), IEEE, 出版日 2012年, 査読付, We have resolved the vibrational wave-packet dynamics of D-2(+) with a period of similar to 20-fs generated with sub-10 fs XUV harmonic field. The real-time evolution is probed with the sub-10 fs VUV and DUV harmonic fields.
研究論文（国際会議プロシーディングス）, 英語 - Nonlinear Fourier-transform spectroscopy of D-2 using high-order harmonic radiation
Yusuke Furukawa; Yasuo Nabekawa; Tomoya Okino; Sebastien Saugout; Kaoru Yamanouchi; Katsumi Midorikawa
PHYSICAL REVIEW A, AMER PHYSICAL SOC, 82巻, 1号, 掲載ページ B118-B121, 出版日 2010年07月, 査読付, We have determined the multiphoton ionization and dissociation pathways of D-2 with the simultaneous irradiation of the high-order harmonic fields and the low-order harmonic fields of Ti:sapphire laser pulses in the visible-vacuum ultraviolet region with the aid of a nonlinear Fourier-transform spectroscopy. By analyzing the interferometric autocorrelation signal of the measured velocity map images of D+, we were able to decompose the measured momentum distribution into three momentum distribution images representing the three distinct dissociation pathways, which are sequentially two-photon absorption processes of D-2 via the electronic ground state ( X (2)Sigma(+)(g)) of D-2(+) to the first excited state (A(2)Sigma(+)(u)), leading to the dissociation into D+ + D.
研究論文（学術雑誌）, 英語 - Observation of Complex Optical Processes in ZnSe under Extreme Optical Excitation from a Kilojoule-Class Nd:Glass Laser
Tomoharu Nakazato; Yusuke Furukawa; Toshihiko Shimizu; Marilou Cadatal-Raduban; Elmer Estacio; Nobuhiko Sarukura; Akiyuki Shiroshita; Kazuto Otani; Toshihiko Kadono; Keisuke Shigemori; Hiroshi Azechi
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOC APPLIED PHYSICS, 49巻, 6号, 掲載ページ 0626011-0626013, 出版日 2010年06月, 査読付, In this paper, we report on three-photon fluorescence and the possible observation of other complex optical processes in a ZnSe crystal for a kilojoule-class, 100 ps pulse, Nd: glass laser excitation. The emission properties of the ZnSe crystal and its excitation energy dependence were investigated under low and high-energy excitations. A 15 to 10 nm full width at half maximum (FWHM) spectral collapse, a 5 nm blue shift, and a shortened lifetime of fluorescence under high-energy excitation could indicate an amplified spontaneous emission. These findings present the feasibility of investigating the dynamics and spectral properties of three-photon fluorescence and other complex nonlinear optical processes in ZnSe at an extremely high excitation energy. (C) 2010 The Japan Society of Applied Physics
研究論文（学術雑誌）, 英語 - Systematic Study on Ce:LuLiF4 as a Fast Scintillator Using Storage Ring Free-Electron Lasers
Tomoharu Nakazato; Yusuke Furukawa; Marilou Cadatal-Raduban; Minh Pham; Toshihiro Tatsumi; Ayumi Saiki; Yasunobu Arikawa; Nobuhiko Sarukura; Hiroaki Nishimura; Hiroshi Azechi; Kunioki Mima; Tsuguo Fukuda; Masahito Hosaka; Masahiro Katoh; Nobuhiro Kosugi
JAPANESE JOURNAL OF APPLIED PHYSICS, IOP PUBLISHING LTD, 49巻, 12号, 掲載ページ 122602, 出版日 2010年, 査読付, Ce:LuLiF4 is evaluated as a fast scintillator using a storage ring free-electron laser operating in the deep-ultraviolet region. The relatively flat spectral response across its absorption bands makes this material an attractive scintillator for various excitation sources. Its decay time is acceptable for ignition timing in fast-ignition, inertial confinement nuclear fusion using laser. This report is the first systematic study on Ce:LuLiF4 as a scintillator, wherein the storage ring free-electron laser is also shown as a powerful tool for material survey. (C) 2010 The Japan Society of Applied Physics
研究論文（学術雑誌）, 英語 - Development of Vacuum Ultraviolet Streak Camera System for the Evaluation of Vacuum Ultraviolet Emitting Materials
Yusuke Furukawa; Marilou Cadatal; Kohei Yamanoi; Satoru Takatori; Minh Pham; Elmer Estacio; Tomoharu Nakazato; Toshihiko Shimizu; Nobuhiko Sarukura; Ken Kitano; Kozo Ando; Koro Uchiyama; Yoshio Isobe; Kentaro Fukuda; Toshihisa Suyama; Takayuki Yanagida; Yuui Yokota; Akira Yoshikawa; Fumio Saito
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOC APPLIED PHYSICS, 48巻, 9号, 掲載ページ 96503, 出版日 2009年09月, 査読付, Details of the design and development of a bright vacuum ultraviolet Seya-Namioka type spectrometer and streak camera system with reflection-type input optics is presented. The Seya-Namioka spectrometer has a 40 mm by 45 mm holographic grating with a groove density of 600 grooves/mm, linear dispersion of 8 nm/mm, and effective F-number of 4.2. To eliminate loss of light by absorption, the streak camera imaging unit uses Al and MgF2 coated imaging optics with at least 80% reflection from 125-850 nm and has an effective F-number of 4. It is equipped with a synchronized scan unit that can be tuned to 82 MHz and a slow scan speed unit that can measure up to 2-MHz single event. Temporal response of the system at the 20-ns scanning range is evaluated to be around 260 ps. (C) 2009 The Japan Society of Applied Physics
研究論文（学術雑誌）, 英語 - Interferometry of Attosecond Pulse Trains in the Extreme Ultraviolet Wavelength Region
Yasuo Nabekawa; Toshihiko Shimizu; Yusuke Furukawa; Eiji J. Takahashi; Katsumi Midorikawa
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 102巻, 21号, 掲載ページ 2922-2924, 出版日 2009年05月, 査読付, The temporal coherence of an attosecond optical field in the extreme ultraviolet wavelength region can be defined in terms of the extent of interference in time domain. We successfully measured this phenomenon both with and without spectral decomposition. We also report the results of using this approach to directly observe both symmetry and symmetry breaking of interference fringes in an attosecond pulse train.
研究論文（学術雑誌）, 英語 - Fourier Spectroscopy of Fragmentation of D-2(+) Irradiated with Attosecond Pulse Trains
Yusuke Furukawa; Tomoya Okino; Kaoru Yamanouchi; Sebastien Saugout; Yasuo Nabekawa; Katsumi Midorikawa
2009 CONFERENCE ON LASERS AND ELECTRO-OPTICS AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2009), VOLS 1-5, IEEE, 掲載ページ 2491-+, 出版日 2009年, The kinetic energy release of the D+ fragment ion from D-2 molecule is measured using an interferometric autocorrelation technique. The interference fringes of the omega, 3 omega, and 5 omega fields emerge on the D+ fragment signals. (C)2009 Optical Society of America
研究論文（国際会議プロシーディングス）, 英語 - Development of Vacuum Ultraviolet Streak Camera System with Bright Spectrograph for the Evaluation of Luminescent Materials
Marilou Cadatal; Yusuke Furukawa; Kouhei Yamanoi; Satoru Takatori; Minh Pham; Elmer Estacio; Tomoharu Nakazato; Toshihiko Shimizu; Nobuhiko Sarukura; Ken Kitano; Kozo Ando; Koro Uchiyama; Yoshio Isobe; Kentaro Fukuda; Toshihisa Suyama; Takayuki Yanagida; Akira Yoshikawa; Fumio Saito
Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, OSA, 出版日 2009年, 査読付, Bright vacuum ultraviolet Seya-Namioka type spectrometer and streak camera system with reflection-type input optics is developed and used to measure 175-nm Nd3+:LaF3 fluorescence with 7-ns decay time. © 2009 Optical Society of America.
研究論文（国際会議プロシーディングス） - Three-photon Lasing from ZnSe Excited by a kilojoule-class Nd:Glass Laser
Yusuke Furukawa; Tomoharu Nakazato; Toshihiro Shimizu; Marilou Cadatal; Elmer Estacio; Nobuhiko Sarukura; Akiyuki Shiroshita; Kazuto Otani; Toshihiko Kadono; Keisuke Shigemori; Hiroshi Azechi
2009 CONFERENCE ON LASERS AND ELECTRO-OPTICS AND QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE (CLEO/QELS 2009), VOLS 1-5, IEEE, 掲載ページ 1609-1610, 出版日 2009年, 査読付, Three-photon fluorescence and lasing from ZnSe was observed for a kilojoule-class, 100 picosecond pulse, Nd:glass laser excitation. In this work, the emission properties and its excitation energy dependence were investigated for low and high-energy excitation. (C) 2009 Optical Society of America
研究論文（国際会議プロシーディングス）, 英語 - Observation of birefringence in BBO crystals in the terahertz regime
○Shigeki Saito; Elmer Estacio; Tomoharu Nakazato; Yusuke Furukawa; Toshihiko Shimizu; Nobuhiko Sarukura; Marilou Cadatal; Minh Hong Pham; Carlito Ponseca; Jr; Hiroshi Mizuseki; Yoshiyuki Kawazoe
Journal of Crystal Growth, ELSEVIER SCIENCE BV, 311巻, 3号, 掲載ページ 895-898, 出版日 2009年01月, 査読付, We present experimental results of birefringence in beta barium borate (beta-BaB(2)O(4) or BBO) crystals in the 0.2-1 terahertz (THz) frequency range. Standard polarized THz-transmission spectroscopy of a BBO Slab Cut under 90 was performed at different azimuthal orientations to determine the ordinary and extraordinary refractive indices. An average Lambda n/n value of 0.118 was calculated. Moreover. azimuthal angle-dependent absorption was observed at about 0.65THz, in close agreement with calculations based on first principles. Our calculations showed the absorption feature was due to the low-frequency phonon modes of the [B(3)O(6)](3) rings. These results suggest that a BBO-based THz optical-parametric-oscillator design is feasible. (C) 2008 Elsevier B.V. All rights reserved.
研究論文（学術雑誌）, 英語 - Hydrothermal-method-grown ZnO single crystal as fast EUV scintillator for future lithography
Tomoharu Nakazato; Yusuke Furukawa; Momoko Tanaka; Toshihiro Tatsumi; Masaharu Nishikino; Hiroshi Yamatani; Keisuke Nagashima; Toyoaki Kimura; Hidetoshi Murakami; Shigeki Saito; Toshihiko Shimizu; Nobuhiko Sarukura; Hiroaki Nishimura; Kunioki Mima; Yuji Kagamitani; Dirk Ehrentraut; Tsuguo Fukuda
JOURNAL OF CRYSTAL GROWTH, ELSEVIER SCIENCE BV, 311巻, 3号, 掲載ページ 875-877, 出版日 2009年01月, 査読付, The temperature dependence of scintillation properties of a hydrothermal-method-grown zinc oxide (ZnO) emission is investigated using a nickel-like silver laser emitting at 13.9 nm. A broad peak at 386 nm with a full-width at half-maximum (FWHM) of 15 nm at room temperature (298 K) is obtained. The peak position tends to be blue shifted while the FWHM becomes narrower when the crystal temperature is decreased to 25 K. Streak images fitted by a double experiential decay reveal that the measured emission decay at 105 K was iota(1) = 0.88 ns and iota(2) = 2.7 ns. This decay time of a few nanoseconds is suitable for lithographic applications and is sufficiently short for the characterization of laser plasma extreme ultraviolet (EUV) sources with nanosecond durations. (C) 2008 Elsevier B.V. All rights reserved.
研究論文（学術雑誌）, 英語 - Efficient ejection of H(3)(+) from hydrocarbon molecules induced by ultrashort intense lalifeser fields
Kennosuke Hoshina; Yusuke Furukawa; Tomoya Okino; Kaoru Yamanouchi
JOURNAL OF CHEMICAL PHYSICS, AMER INST PHYSICS, 129巻, 10号, 掲載ページ B118-B121, 出版日 2008年09月, 査読付, The ejection processes of hydrogen molecular ion H(3)(+) from 12 kinds of hydrocarbon molecular species, methanol, ethanol, 1-propanol, 2-propanol, acetone, acetaldehyde, methane, ethane, ethylene, allene, 1,3-butadiene, and cyclohexane, induced by intense laser fields (similar to 10(14) W/cm(2)) have been investigated by time-of-flight mass spectroscopy. The observation of the H(3)(+) production with the kinetic energy range of 3.5-5.0 eV from doubly ionized ethylene, allene, 1,3-butadiene, and cyclohexane, which have no methyl groups, showed the existence of the ultrafast hydrogen migration processes that enables three hydrogen atoms to come together to form H(3)(+) within a hydrocarbon molecule. (c) 2008 American Institute of Physics.
研究論文（学術雑誌）, 英語 - Temperature dependence of scintillation properties for a hydrothermal-method-grown zinc oxide crystal evaluated by nickel-like silver laser pulses
Yusuke Furukawa; Momoko Tanaka; Tomoharu Nakazato; Toshihiro Tatsumi; Masaharu Nishikino; Hiroshi Yamatani; Keisuke Nagashima; Toyoaki Kimura; Hidetoshi Murakami; Shigeki Saito; Nobuhiko Sarukura; Hiroaki Nishimura; Kunioki Mima; Yuji Kagamitani; Dirk Ehrentraut; Tsuguo Fukuda
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, OPTICAL SOC AMER, 25巻, 7号, 掲載ページ B118-B121, 出版日 2008年07月, 査読付, The scintillation properties of a hydrothermal-method-grown zinc oxide (ZnO) crystal in the extreme ultraviolet region are evaluated using a nickel-like silver laser with an emission wavelength of 13.9 nm. The temperature dependence of the scintillation properties of the ZnO emission at a wavelength of similar to 380 nm is investigated. The emission exhibits a broad peak at 386 nm with a full width at half-maximum (FWHM) of 15 nm at room temperature (298 K). Decreasing the ZnO crystal temperature to 25 K causes the peak position to be blue-shifted by 12 nm while the FWHM becomes narrower by 9 nm as compared with the room temperature case. (C) 2008 Optical Society of America.
研究論文（学術雑誌）, 英語 - Birefringence of beta-BaB(2)O(4) crystal in the terahertz region for parametric device design
Elmer Estacio; Shigeki Saito; Tomoharu Nakazato; Yusuke Furukawa; Nobuhiko Sarukura; Marilou Cadatal; Minh Hong Pham; Carlito Ponseca; Hiroshi Mizuseki; Yoshiyuki Kawazoe
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 92巻, 9号, 掲載ページ 91116, 出版日 2008年03月, 査読付, beta-BaB(2)O(4) (BBO) was found to have huge birefringence in the 0.1-1.1 THz frequency region. Polarized terahertz transmission spectroscopy revealed a Delta n/n value of about 0.12 +/- 0.02. This result could be related to a polarization-dependent absorption that was observed at about 0.65 THz; in close agreement with first principles-calculations, showing this to be due to low-frequency phonon modes of the [B(3)O(6)](3)-rings. These findings suggest the utilization of the birefringent properties of BBO for optical parametric devices including amplifiers and oscillators, operating in the terahertz regime. (C) 2008 American Institute of Physics.
研究論文（学術雑誌）, 英語 - Characterization of Ce:LuLiF4 as Fast Scintillator Using Storage Ring Free-Electron Lasers
Yusuke Furukawa; Tomoharu Nakazato; Marilou Cadatal; Minh Pham; Toshihiro Tatsumi; Ayumi Saiki; Yasunobu Arikawa; Nobuhiko Sarukura; Hiroaki Nishimura; Hiroshi Azechi; Kunioki Mima; Tsuguo Fukuda; Masahito Hosaka; Masahiro Katoh; Nobuhiro Kosugi
2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9, IEEE, 掲載ページ 256-+, 出版日 2008年, 査読付, Ce:LuLiF4 as fast scintillator is evaluated using a storage ring free-electron laser operated in deep ultraviolet region. The response time is found to be varied for the excitation of the different absorption band. (C) 2008 Optical Society of America
研究論文（国際会議プロシーディングス）, 英語 - Terahertz birefringence of beta-BaB2O4 (BBO) Crystal
Elmer Estacio; Shigeki Saito; Tomobaru Nakazato; Yusuke Furukawa; Toshihiro Tatsumi; Minh Hong Pham; Marilou Cadatal; Carlito Ponseca; Hiroshi Mizuseki; Yoshiyuld Kawazoe; Nobuhiko Sarukura
2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9, IEEE, 掲載ページ 1588-+, 出版日 2008年, 査読付, Birefringence was observed for a beta-BaB2O4 crystal in the 0.1 to 1.1 terahertz region. The calculated An value was similar to 0.296. Moreover, an angle-dependent absorption band observed at similar to 0.65 terahertz is attributed to low-frequency phonon modes. (C) 2008 Optical Society of America
研究論文（国際会議プロシーディングス）, 英語 - UV Fluorescence of Hydrothermal Method Grown ZnO for Fast EUV Scintillators
Yusuke Furukawa; Momoko Tonaka; Masaharu Nishikino; Hiroshi Yamatani; Tomoharu Nakazato; Toshihiro Tatsumi; Shigeld Saito; Hidetoshi Murakami; Nobuhiko Sarukura; Hiroaki Nishimura; Kunioki Mima; Keisuke Nagashima; Toyoaki Kimura; Yuji Kagamitani; Tsuguo Fukuda
2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9, IEEE, 掲載ページ 258-+, 出版日 2008年, 査読付, The scintillation properties of a hydrothermal method grown ZnO crystal are evaluated for EUV laser excitation. The excitonic emission decay at 380-nm is determined to be 1.3-ns, almost identical to ultraviolet laser excitation cases. (C) 2008 Optical Society of America
研究論文（国際会議プロシーディングス）, 英語 - Hydrothermal method grown large-sized zinc oxide single crystal as fast scintillator for future extreme ultraviolet lithography
Momoko Tanaka; Masaharu Nishikino; Hiroshi Yamatani; Keisuke Nagashima; Toyoaki Kimura; Yusuke Furukawa; Hidetoshi Murakami; Shigeki Saito; Nobuhiko Sarukura; Hiroaki Nishimura; Kunioki Mima; Yuji Kagamitani; Dirk Ehrentraut; Tsuguo Fukuda
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 91巻, 23号, 掲載ページ 231117, 出版日 2007年12月, 査読付, The scintillation properties of a hydrothermal method grown zinc oxide (ZnO) crystal are evaluated for extreme ultraviolet (EUV) laser excitation at 13.9 nm wavelength. The exciton emission lifetime at around 380 nm is determined to be 1.1 ns, almost identical to ultraviolet laser excitation cases. This fast response time is sufficiently short for characterizing EUV lithography light sources having a few nanoseconds duration. The availability of large size ZnO crystal up to 3 in. is quite attractive for future lithography and imaging applications.
研究論文（学術雑誌）, 英語 - ZnO as fast EUV scintillator for the next generation lithography
Momoko Tanaka; Masaharu Nishikino; Keisuke Nagashima; Toyoaki Kimura; Yusuke Furukawa; Hidetoshi Murakami; Nobuhiko Sarukura; Hiroshi Yamatani; Akira Yoshikawa; Tsuguo Fukuda
2007 PACIFIC RIM CONFERENCE ON LASERS AND ELECTRO-OPTICS, VOLS 1-4, IEEE, 掲載ページ 1312-+, 出版日 2007年, 査読付, Using Ni-like Ag extreme ultraviolet (EUV) laser operated at 13.9-nm, ZnO is shown to be the excellent scintillator in this wavelength region with sufficiently short response time of less than 3 nsec and prominent peak fluorescence originated form exciton at 380 nm.
研究論文（国際会議プロシーディングス）, 英語 - Dissociation of water molecules in carrier-envelope phase controlled intense few-cycle laser fields
Hidetoshi Nakano; Atsushi Ishizawa; Yusuke Furukawa; Katsuya Oguri; Kaoru Yamanouchi
2007 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2, IEEE, 掲載ページ 372-+, 出版日 2007年, 査読付
研究論文（国際会議プロシーディングス）, 英語 - Three-body sequential Coulomb explosions of CH3OD3+ induced by intense laser fields
Liu Peng; Okino Tomoya; Furukawa Yusuke; Ichikawa Takayuki; Itakura Ryuji; Hoshina Kennosuke; Yamanouchi Kaoru; Nakano Hidetoshi
CHEMICAL PHYSICS LETTERS, 423巻, 1-3号, 掲載ページ 187-191, 出版日 2006年05月20日, 査読付 - Coincidence momentum imaging of ultrafast hydrogen migration in methanol and its isotopomers in intense laser fields
Okino Tomoya; Furukawa Yusuke; Liu Peng; Ichikawa Takayuki; Itakura Ryuji; Hoshina Kennosuke; Yamanouchi Kaoru; Nakano Hidetoshi
CHEMICAL PHYSICS LETTERS, 423巻, 1-3号, 掲載ページ 220-224, 出版日 2006年05月20日, 査読付
MISC
- アト秒非線形フーリエ分子分光 (「フーリエ光学を応用した最先端光科学」解説小特集号)
沖野 友哉; 古川 裕介; 鍋川 康夫
レーザー学会, 出版日 2015年04月, レーザー研究 = The review of laser engineering : レーザー学会誌, 43巻, 4号, 掲載ページ 217-221, 日本語, 0387-0200, 40020463682, AN00255326 - 光で繋ぐ理研の基礎科学 重水素分子の光解離過程の高次高調波フーリエ分光
古川裕介; 鍋川康夫; 清水俊彦; 沖野友哉; 山内薫; 緑川克美
出版日 2009年, エクストリームフォトニクスシンポジウム-光で繋ぐ理研の基礎科学 平成21年, 掲載ページ 79-80, 日本語, 201002282984486500 - Efficient ejection of H-3(+) from hydrocarbon molecules induced by ultrashort intense laser fields (vol 129, art no 104302, 2008)
Kennosuke Hoshina; Yusuke Furukawa; Tomoya Okino; Kaoru Yamanouchi
AMER INST PHYSICS, 出版日 2008年12月, JOURNAL OF CHEMICAL PHYSICS, 129巻, 22号, 英語, その他, 0021-9606, WOS:000261698300052 - アト秒パルス列の発生とその応用
鍋川康夫; 沖野友哉; 清水俊彦; 古川裕介; 山内薫; 緑川克美
出版日 2008年09月02日, 応用物理学会学術講演会講演予稿集, 69th巻, 0号, 掲載ページ 40, 日本語, 200902297638544991 - 軟X線レーザー励起による固体の発光計測
田中 桃子; 古川 裕介; 猿倉 信彦
出版日 2008年07月25日, プラズマ・核融合学会誌, 84巻, 7号, 掲載ページ 443-445, 日本語, 110006835286 - Vacuum ultraviolet optical properties of a micropulling-down-method grown Nd3+:(La-0.9,Ba-0.1)F-2.9
Marilou Cadatal; Yusuke Furukawa; Young-Seok Seo; Shingo Ono; Elmer Estacio; Hidetoshi Murakami; Yasushi Fujimoto; Nobuhiko Sarukura; Masahiro Nakatsuka; Kentaro Fukuda; Rayko Simura; Toshihisa Suyama; Akira Yoshikawa; Fumio Saito
Nd3+: (La1-x,Ba-x,)F3-x (x=0.1) is efficiently grown by the micro-pulling-down method. Characterization of its optical properties reveals that it is transparent in the vacuum ultraviolet region with an absorption edge at around 180 nm. It has fluorescence centered at 175 nm with a bandwidth of 12 nm and a lifetime of 6.1 ns as measured by a vacuum ultraviolet streak camera and spectrometer combination. It is proposed to be suitable as a vacuum ultraviolet scintillator and a potential laser material. (C) 2008 Optical Society of America., OPTICAL SOC AMER, 出版日 2008年07月, JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, 25巻, 7号, 掲載ページ B27-B31, 英語, 0740-3224, 1520-8540, 80019692748, WOS:000258014000005 - EUVレーザーを用いた固体の時間分解分光
猿倉 信彦; 永島 圭介; 木村 豊秋; 鏡谷 勇二; 福田 承生; 古川 裕介; 村上 英利; 斎藤 繁喜; 西村 博明; 三間 圀興; 田中 桃子; 錦野 将元; 山谷 寛
出版日 2008年, レーザー研究, 36巻, 0号, 掲載ページ 77-78, 日本語, 0387-0200, 130004466086 - Dissociation of water molecule in intense laser fields and its dependence on pulse duration
Hidetoshi Nakano; Yusuke Furukawa; Atsushi Ishizawa; Kennosuke Hoshina; Kaoru Yamanouchi
We observed the momentum distributions of protons ejected from water molecule in intense sub-10-fs laser pulses. We found that the peak position of protons generated through non-sequential ionization is insensitive to the pulse duration. © 2006 Optical Society of America., 出版日 2006年12月01日, Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, CLEO/QELS 2006, 55649085306 - 炭化水素分子内での強光子場誘起水素マイグレーション
沖野友哉; 古川裕介; LIU Peng; 板倉隆二; 星名賢之助; 山内薫; 中野秀俊
出版日 2006年08月24日, 分子構造総合討論会講演要旨集(CD-ROM), 2006巻, 掲載ページ 3P125, 日本語, 200902226701203542 - 強光子場におけるメチルアセチレンとアレンの解離性イオン化機構
森岡嗣人; 古川裕介; 沖野友哉; 星名賢之助; 山内薫
出版日 2006年08月24日, 分子構造総合討論会講演要旨集(CD-ROM), 2006巻, 掲載ページ 2P118, 日本語, 200902250961139196 - Ejection dynamics of hydrogen molecular ions from methanol in intense laser fields
T. Okino; Y. Furukawa; P. Liu; T. Ichikawa; R. Itakura; K. Hoshina; K. Yamanouchi; H. Nakano
The ejection of hydrogen molecular ions from two-body Coulomb explosion processes of methanol (CH3OH, CD3OH and CH3OD) in an intense laser field (800 nm, 60 fs, 0.2 PW cm-2) is investigated by a coincidence momentum imaging method. From the coincidence momentum maps, the ejection processes of hydrogen molecular ions, CH 3OH2+→ Hm+ + CH (3-m)OH+(m ≤ 2, 3), CD3OH2+→ Dm+ + CH(3-m)OH+(m ≤ 2, 3) and CH3OD2+→ Hm+ + CH (3-m)OD+(m ≤ 2, 3), are identified. Based on the results obtained with isotopically substituted methanol, the isotope effect on the ejection process of hydrogen molecular ions is discussed. Furthermore, the ejection of H/D exchanged hydrogen molecular ions (HD+, HD 2+ and H2D+) is identified, and the timescales for the H/D exchanging processes are estimated from the extent of anisotropy in the ejection directions. © 2006 IOP Publishing Ltd., 出版日 2006年07月14日, Journal of Physics B: Atomic, Molecular and Optical Physics, 39巻, 0953-4075, 33745503209 - コインシデンス運動量画像法による強光子場中メタノール分子の超高速水素ダイナミクス
沖野友哉; 古川裕介; LIU Peng; 市川太佳之; 板倉隆二; 星名賢之助; 山内薫; 中野秀俊
出版日 2006年06月06日, 化学反応討論会講演要旨集, 22nd巻, 掲載ページ 64-65, 日本語, 200902260166592988 - 強光子場による炭化水素分子からのH3+放出
星名賢之助; 古川裕介; LIU Peng; 沖野友哉; 板倉隆二; 山内薫
出版日 2006年06月06日, 化学反応討論会講演要旨集, 22nd巻, 掲載ページ 134, 日本語, 200902282229093360 - コインシデンス運動量画像法による強光子場中メタノール分子からのH3イオン放出の観測
沖野友哉; 古川裕介; LIU Peng; 市川太佳之; 板倉隆二; 星名賢之助; 山内薫; 中野秀俊
出版日 2006年03月22日, 応用物理学関係連合講演会講演予稿集, 53rd巻, 3号, 掲載ページ 1164, 日本語, 200902279315468155 - 強光子場中メタノール分子のH3+イオンの放出と超高速水素移動過程
沖野友哉; 古川裕介; LIU Peng; 市川太佳之; 板倉隆二; 星名賢之助; 山内薫; 中野秀俊
出版日 2006年03月13日, 日本化学会講演予稿集, 86th巻, 1号, 掲載ページ 254, 日本語, 0285-7626, 200902246118883927 - Coincidence momentum imaging of ejection of hydrogen molecular ions from methanol in intense laser fields
Tomoya Okino; Yusuke Furukawa; Peng Liu; Takayuki Ichikawa; Ryuji Itakura; Kennosuke Hoshina; Kaoru Yamanouchi; Hidetoshi Nakano
Two-body Coulomb explosion processes of methanol (CH3OH) in an intense laser field (0.2 PW/cm2, 60 fs) are investigated by the coincidence momentum imaging method. In the coincidence momentum images, the hydrogen ejection processes, CH3OH2+→Hm++CH(3-m)OH+(m=1-3), are securely identified. From the anisotropy in the angular distributions of the fragment ions, the lifetimes of the corresponding precursor ions CH3OH 2+ are estimated to be 70-290 fs for the H+ ejection, 110-550 fs for the H2+ ejection, and much longer than 1.4 ps for the H3+ ejection. © 2005 Elsevier B.V. All rights reserved., 出版日 2006年02月15日, Chemical Physics Letters, 419巻, 掲載ページ 223-227, 0009-2614, 31544466504 - Ejection of triatomic hydrogen molecular ion from methanol in intense laser fields
Yusuke Furukawa; Kennosuke Hoshina; Kaoru Yamanouchi; Hidetoshi Nakano
The ejection of a triatomic or diatomic hydrogen molecular ion from methanol (CH3OH and CD3OH) in intense laser fields (86 fs, 800 nm, ≈1014W/cm2) is investigated based on the momentum vector distributions of the fragment ions measured by the mass-resolved momentum imaging technique. From the relative yield of D3+,HD2+,D2+ and HD+ejected from CD3OH2+and the anisotropic distributions of their momentum vectors, the rates of the formation of triatomic (D3+andHD2+) and diatomic (D2+ and HD+) fragment ions, kt= 0.15 ps-1and kd= 0.31 ps-1, respectively, and the H/D exchange rate, kex= 0.13 ps-1, are derived. © 2005 Elsevier B.V. All rights reserved., 出版日 2005年10月03日, Chemical Physics Letters, 414巻, 掲載ページ 117-121, 0009-2614, 28844496664 - 強レーザー場中のメタノール分子の水素分子イオン生成過程
沖野友哉; 古川裕介; 板倉隆二; 星名賢之助; 山内薫; 中野秀俊
出版日 2005年08月23日, 原子衝突研究協会研究会講演概要集, 30th巻, 掲載ページ 77, 日本語, 200902204058612550 - 強レーザー場によるメタノールの解離性イオン化過程
古川裕介; 星名賢之助; 山内薫; 中野秀俊
出版日 2005年06月01日, 化学反応討論会講演要旨集, 21st巻, 掲載ページ 131, 日本語, 200902273184994281 - 高強度超短パルス軟X線高調波による多原子分子の光イオン化
星名賢之助; 菱川明栄; 佐甲徳栄; 古川裕介; 山内薫; 鍋川康夫; 高橋栄治; 長谷川宗良; 緑川克美
出版日 2005年03月29日, 応用物理学関係連合講演会講演予稿集, 52nd巻, 3号, 掲載ページ 1235, 日本語, 200902286412662590 - 強光子場におけるアセトンの解離性イオン化過程
古川裕介; 星名賢之助; 山内薫; 中野秀俊
出版日 2005年03月11日, 日本化学会講演予稿集, 85th巻, 1号, 掲載ページ 320, 日本語, 0285-7626, 200902233171691377 - Ejection of hydrogen molecular Ion from hydrocarbon molecules in intense laser fields
Y. Furukawa; K. Hoshina; T. Sako; K. Yamanouchi; H. Nakano
The ejection dynamics of hydrogen molecular ions from hydrocarbon molecules in intense laser fields is investigated. On the basis of the momentum vector distributions of H2+ and H3+, the mechanism of their formation is discussed., 出版日 2005年, IQEC, International Quantum Electronics Conference Proceedings, 2005巻, 掲載ページ 580-581, 英語, 33846549051 - 高励起分子の解離性イオン化過程 XUV域高次高調波光源によるアプローチ
福田祐仁; 岩前敦; 古川裕介; 星名賢之助; 菱川明栄; 山内薫
出版日 2002年03月11日, 日本化学会講演予稿集, 81st巻, 1号, 掲載ページ 312, 日本語, 0285-7626, 200902129284537585 - OCS+X2Π状態のRenner‐Teller相互作用
古川裕介; 福田祐仁; 星名賢之助; 菱川明栄; 山内薫
出版日 2000年09月27日, 分子構造総合討論会講演要旨集, 2000巻, 掲載ページ 616, 日本語, 200902140869121116 - Micro-Pulling Down Method Grown Ce:LiCAF as Ultraviolet Laser
Marilou Cadatal; Minh Pham; Toshihiro Tatsumi; Ayumi Saiki; Yusuke Furukawa; Elmer Estacio; Nobuhiko Sarukura; Toshihisa Suyama; Kentaro Fukuda; Kyoung Jin Kim; Akira Yoshikawa; Fumio Saito
We report the first successful micro-pulling down method growth and ultraviolet emission from a Ce:LiCAF crystal. With two-side pumping configuration, 23% slope efficiency is obtained from the 290-nm emission of a 30mm-long, 2mm-wide Brewster-cut crystal. (c) 2008 Optical Society of America, IEEE, 出版日 1905年06月30日, 2008 CONFERENCE ON LASERS AND ELECTRO-OPTICS & QUANTUM ELECTRONICS AND LASER SCIENCE CONFERENCE, VOLS 1-9, 掲載ページ 1220-+, 英語, WOS:000260498400612
書籍等出版物
講演・口頭発表等
- 単一縦横モード発振を維持したレーザーの高出力化
隈元 清哉; 大饗 千彰; 古川 祐介; 桂川 眞幸
口頭発表（一般）, 日本語, 2018年第79回応用物理学会秋季学術講演会, 名古屋国際会議場
発表日 2018年09月19日 - Multi-photon Dissociative Ionization of D-2 Probed by a-Few-Pulse Attosecond Pulse Train
Tomoya Okino; Yusuke Furukawa; Yasuo Nabekawa; Katsumi Midorikawa
口頭発表（一般）, 英語, 2017 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC), Munich, Germany, 国際会議
発表日 2017年06月27日 - Development of a small module for monitoring of laser operation environment temperature of a resonance scattering lidar observation
Ryo Tani; Mitsumu Ejiri; Takanori Nishiyama; Katsuhiko Tsuno; Takuji Nakamura; Toru Takahashi; Yusuke Furukawa; Hitoki Yoneda
ポスター発表, 英語, The Seventh Symposium on Polar Science, 国際会議
発表日 2016年11月29日 - ライダー用可搬型注入同期チタンサファイアレーザー
古川裕介; 大饗千彰; 鹿内翔平; 谷 遼; 米田仁紀; 桂川眞幸
口頭発表（一般）, 日本語, 第34回レーザセンシングシンポジウム, レーザ・レーダ研究会, 長野県下高井郡, 国内会議
発表日 2016年09月08日
共同研究・競争的資金等の研究課題
- アト秒量子波束ダイナミックスの研究
鍋川 康夫; 高橋 栄治; 古川 裕介; 沖野 友哉; 神田 夏輝; アブドルレザ アマニ; リン ユーチー
日本学術振興会, 科学研究費助成事業, 国立研究開発法人理化学研究所, 基盤研究(A), アト秒パルス列を用いて、簡単な構造の分子の超高速ダイナミックスの観測と反応経路の制御に成功した。最初の実験ではH2+ 分子の振動波束が生成される際に~1fs程度の準備時間が必要であることが明らかになった (Nat. Commun. 6:8197 (2015).)。次に、N2をターゲットとした実験でアト秒電子波束生成が確認された(Sci. Adv. 1, e1500356 (2015))。H2+ 分子については、振動波束の動きを利用することにより乖離経路を2pσu状態から2pπu 状態へ、わずか8fsの遅延時間操作で切変えることに成功した(Nat. Commun. 7:12835(2016))。, 26247068
研究期間 2014年04月01日 - 2019年03月31日 - 周期可変アト秒パルス列による量子制御
鍋川 康夫; 高橋 栄治; 古川 裕介; 金井 恒人; 沖野 友哉
日本学術振興会, 科学研究費助成事業, 独立行政法人理化学研究所, 基盤研究(A), 我々は本研究に於いて、波長1.2μmから2.1μmに及ぶ広帯域赤外レーザーパルス光源を開発した。今後の改良により、高次高調波発生による原子・分子研究用の単一アト秒光源に発展可能である。既存のチタンサファイアレーザー高次高調波ビームラインを用いた実験において、サブ20fsで高速運動するD_<2+>/H_<2+> の振動波束の様子を捉えた。これはサブ10fsの極端紫外光で生成し、真空紫外光でプローブした量子波束の最初の観測事例である。, 21244066
研究期間 2009年 - 2012年 - 分子イオンの電子励起状態の光解離ダイナミクス
- Photodissociation of the electronically excited state of molecular ions
