MASAYOSHI WATANABE
| Emeritus Professor etc. | Emeritus Professor |
Researcher Information
Career
- 01 Apr. 2019
電気通信大学, 保健管理センター, センタ―長 - 01 Apr. 2018
電気通信大学, 副学長 - 01 Apr. 2017 - 31 Mar. 2018
同研究教育技師部, 部長 - 01 Apr. 2015 - 31 Mar. 2018
同共通教育部キャリア教育部会, 部会長 - 01 Apr. 2011 - 31 Mar. 2012
同先進理工学専攻, 専攻長・学科長（兼務） - 01 Jan. 2008 - 31 Mar. 2009
同電子工学科, 学科長 - 01 Apr. 2006
電気通信大学, 教授 - Apr. 2001 - Mar. 2006
（独）情報通信研究機構（2004/3まで通信総合研究所）, 研究主管・グループリーダー（兼務） - Apr. 1990 - Mar. 2001
郵政省 通信総合研究所 関西先端研究センター, 主任研究官／室長 - Jul. 1982 - Apr. 1990
東京大学 物性研究所, 技官／教務職員／助手 - Apr. 1980 - Jul. 1982
（株）東芝 生産技術研究所
Educational Background
Research Activity Information
Paper
- Title: Frequency stabilization of dual-mode microchip laser by means of beat frequency stabilization
Iyon Titok Sugiarto; Masayoshi Watanabe; Satoshi Sunada; Masaharu Hyodo
Optical Review, OPTICAL SOC JAPAN, 27, 1, 98-107, 01 Feb. 2020, Peer-reviwed, The stabilization of the laser oscillation frequency of a dual-mode microchip laser was demonstrated by stabilizing the beat frequency generated by the two simultaneously oscillating longitudinal modes. In the experiment, a beat frequency of 101 GHz was stabilized to +/- 50 kHz using negative feedback control. As a result, the fluctuation of the laser oscillation frequency was finally stabilized to +/- 50 MHz or less within the resolution of the measurement instrument with an estimated short-term fluctuation of +/- 3.3 MHz. Furthermore, using this technique, the initial drift of the laser oscillation frequency was significantly reduced, and the linear sweep operation of the laser oscillation frequency was successfully demonstrated by linearly sweeping the beat frequency over 30 MHz while maintaining locking. Our technique is essentially robust and suitable for the miniaturization of the system in the future.
Scientific journal, English - Experimental observation of three-photon interference between a two-photon state and a weak coherent state on a beam splitter
Tingyu Li; Saburo Sakurai KatuyukiKasai; Lirong Wang; Masayoshi Watanabe; Yun Zhang
Optics Express, OSA, 26, 16, 20442-20449, 2018, Peer-reviwed
Scientific journal, English - Observation of two-photon interference with continuous variables via homodyne detection
Daohua WU; K. Kasai; M. Watanabe; Y. Zhang
The Europian Phisical Journal D, 71, 260, Oct. 2017, Peer-reviwed
Scientific journal, English - Controlling quantum interference in phase space with amplitude
Yinghong Xue; Tingyu Li; Katsuyuki Kasai; Yoshiko Okada-Shudo; Masayoshi Watanabe; Yun Zhang
scientific reports, 7, 22291-1-22291-6, 23 May 2017, Peer-reviwed
Scientific journal, English - Characteristics of pulse width for an enhanced second harmonic generation
Yun Zhang; Masaharu Hyodo; Yoshiko Okada-Shudo; Yun Zhu; Xiaoyang Wang; Yong Zhu; Guiling Wang; Chuangtian Chen; Shuntaro Watanabe; Masayoshi Watanabe
OPTICS COMMUNICATIONS, ELSEVIER SCIENCE BV, 387, 241-244, Mar. 2017, Peer-reviwed, Temporal characteristics of a cavity enhancement second harmonic (SH) generation for picosecond laser pulse are investigated. We experimentally measured pulse width changes that were indued by group velocity mismatching (GVM), SH process, and enhancement cavity. It indicates that the generated pulse width is a combined effect of the GVM and SH process. Meanwhile, the effect of the enhancement cavity can be avoided by controlling its free spectrum range. A interferometric autocorrelator with a KBBF-PCD as nonlinear crystal is also composed and this extends the measurement light wavelength below 410 nm.
Scientific journal, English - Directionally selective motion detection with bacteriorhodopsin patterned sensor
Yoshiko Okada-Shudo; Tokimasa Tanabe; Takayuki Mukai; Katsuyuki Kasai; Yun Zhang; Masayoshi Watanabe
SYNTHETIC METALS, ELSEVIER SCIENCE SA, 222, Part B, 249-254, Dec. 2016, Peer-reviwed, A compact and low-cost motion detector based on a light-sensitive protein bacteriorhodopsin is fabricated. We show that a single photocell, which is masked with a pattern, can detect the speed and direction of a moving light without complex software algorithms. When light scans the patterned sensing area, the edges of each pattern produce polarity-reversed photocurrents depending on the light bar's speed and direction. Owing to the asymmetry of the pattern, we can detect two or four directions of the moving light. We intend to exploit this unique property in gestural manipulation with a laser pointer or fingers for remote control systems. (C) 2016 Elsevier B.V. All rights reserved.
Scientific journal, English - Characterization of coherence-or-power selectable operation of an external-cavity semiconductor diode laser
Masaharu Hyodo; Masayoshi Watanabe; Akira Kawakami; Shingo Saito; Masaaki Adachi
APPLIED OPTICS, OPTICAL SOC AMER, 55, 36, 10204-10210, Dec. 2016, Peer-reviwed, The properties of the coherence-or-power selectable operation of an external-cavity semiconductor diode laser through the control of intracavity polarization states have been characterized in detail. In our technique, a diffraction grating and a reflector functioned as a polarization-dependent output coupler, such that the portion of light fed back to the gain medium was readily controlled by rotating the intracavity polarization axis, which resulted in the selectable operation of either a high degree of coherence or a high power for the laser output. We could continuously sweep the correlation widths over a range of approximately one order of magnitude, as well as four-fold output powers by simply rotating the intracavity half-wave plate. We also demonstrated experiments on optical phase locking, using two independent coherence-or-power selectable lasers. (C) 2016 Optical Society of America
Scientific journal, English - Optical phase-locking of two longitudinal modes of a dual-mode laser for millimetre-wave signal generation
M. Hyodo; K. Sato; A. Kawakami; S. Saito; M. Watanabe; M. Adachi
ELECTRONICS LETTERS, INST ENGINEERING TECHNOLOGY-IET, 52, 9, 748-U91, Apr. 2016, Peer-reviwed, Phase-locking of two longitudinal oscillating modes of a dual-mode microchip laser that has 101 GHz longitudinal-mode spacing has been successfully demonstrated by using electronic negative-feedback control. Since the two longitudinal modes were oscillating simultaneously in the same laser cavity, the common-mode fluctuation cancels, resulted in the small required control bandwidth of approximate to 4 kHz. This narrow-bandwidth phase-locking technique is useful for generating high-spectral-purity millimetre-wave signals with a considerably simpler setup.
Scientific journal, English - Coherence-selectable operation of externalcavity semiconductor diode laser by intracavity polarisation control
M. Hyodo; A. Kawakami; S. Saito; M. Watanabe; M. Adachi
ELECTRONICS LETTERS, INST ENGINEERING TECHNOLOGY-IET, 51, 7, 574-U133, Apr. 2015, Peer-reviwed, The operation of an external-cavity semiconductor diode laser with selectable coherence and a tunable wavelength has been successfully demonstrated through the control of the intracavity polarisation state. The laser has an intracavity half-wave plate that is able to rotate the orientation of the polarisation axis with regard to diffraction grating, where the grating acts as a polarisation- and wavelength-selective element. As a result, it was possible to continuously sweep the correlation widths from 230 kHz to 2.0 MHz by simply rotating the half-wave plate.
Scientific journal, English - Generation of tripartite quantum correlation among amplitude-squeezed beams by frequency doubling in a singly resonant cavity
Tingyu Li; Ryohei Mitazaki; Katsuyuki Kasai; Yoshiko Okada-Shudo; Masayoshi Watanabe; Yun Zhang
Physical Review A, 91, 023833-023837, 2015, Peer-reviwed
Scientific journal, English - Low intensity noise and narrow line-width diode laser light at 540nm
L. Wang; R. Tamaki; K. Kasai; Y. Okada-Shudo; M. Watanabe; Y. Zhang
Laser Physics Letters, 12, 055802, 2015, Peer-reviwed
Scientific journal, English - KBBF結晶による準連発生真空紫外コヒーレンス光源開発に向けて
張贇; 山口大智; 陳創天; 渡部俊太郎; 渡辺昌良
レーザー研究, レーザー学会, 43, 524-546, 2015, Peer-reviwed
Scientific journal, Japanese - Generation of quasi-cw deep ultraviolet light below 200 nm by an external cavity with a Brewster-input KBBF prism coupling device
Yun Zhang; Ryota Hoshi; Daichi Yamaguchi; Yoshiko Okada-Shudo; Masayoshi Watanabe; Masaharu Hyodo; Yun Zhu; Xiaoyang Wang; Yong Zhu; Guilin Wang; Chuangtian Chen; Teruto Kanai; Shuntaro Watanabe
Optics Communications, 295, 176-179, 15 May 2013, Peer-reviwed, We report the generation of coherent deep ultraviolet light at 199 nm with a maximum average power of 32 mW by frequency quadrupling a picosecond pulse train from a Ti:sapphire laser. Two frequency-doubling stages were taking place in resonant cavities that can enhance conversion efficiency of second harmonic generations (SHGs). To reduce the extra-loss of the resonant cavity, a Brewster-input KBe2BO3F2 (KBBF) prism coupling device (PCD) was designed and employed in the second stage SHG for the first time. © 2013 Elsevier B.V.
Scientific journal, English - Generation of 1.2W green light using a resonant cavity-enhanced second-harmonic process with a periodically poled KTiOPO4
Yun Zhang; Nobuyuki Hayashi; Hiroshi Matsumori; Ryohei Mitazaki; Yinghong Xue; Yoshiko Okada-Shudo; Masayoshi Watanabe; Katsuyuki Kasai
Opt. Commun., 294, 271-275, 2013, Peer-reviwed
Scientific journal, English - Efficient phase noise suppression of an external-cavity diode-laser by optical filteringand resonant optical feedback
Y. Zhang; S. Miyagawa; K. Kasai; Y. Okada-Shudo; M. Watanabe
Appl. Phys. B, 10.1007/S00340-012-4918-8, 2012, Peer-reviwed
Scientific journal, English - Generation of Quasi-CW Deep Ultraviolet Light below 200 nm by Two Successive Cavity Enhanced Second Harmonic Generators
Yun Zhang; Nobuyoshi Watanabe; Yoshiko Okada-Shudo; Masayoshi Watanabe; Masaharu, Hyodo; Xiaoyang Wang; Yong Zhu; Chuangtian Chen; Teruto Kanai; Shuntaro Watanabe
Jpn. J. Appl. Phys., 50, 042703-1, Apr. 2011, Peer-reviwed
Scientific journal, English - Efficient generation of cold atoms towards a source for atom lithography
Ryuzo Ohmukai; Masaharu Hyodo; Masayoshi Watanabe; Hitoshi Kondo
OPTICAL REVIEW, OPTICAL SOC JAPAN, 16, 1, 11-14, Jan. 2009, Peer-reviwed, We report on the efficient generation of cold rubidium atoms as a potential coherent atom source for atom lithography. We successfully trapped and cooled 2.6 x 10(8) atoms in 5 s with a conventional magneto-optical trap simply by enlarging the diameter of the laser beam to 20 mm. The size of the laser-cooled atom cloud was measured to be 10 x 7 x 7 mm(3). The number of trapped atoms was approximately 10 times as large as that of previous typical results, while the loading time of atoms remained the same.
Scientific journal, English - Generation of quasi-continuous-wave vacuum-ultraviolet coherent light from fourth-harmonic of a Ti:sapphire laser with KBBF crystal
Y. Zhang; Y. Sato; N. Watanabe; R. Ananda; Y. Okada-Shudo; M. Watanabe; M. Hyodo; X. Wang; C. Chen; T. Kanai; S. Watanabe
Optics Express, 17, 8119–8124, 2009
Scientific journal, English - Mirror magneto-optical trap exploiting hexapole-compensated magnetic field
M. Hyodo; K. Nakayama; M. Watanabe; R. Ohmukai
Phys. Rev. A, 76, 013419, 2007, Peer-reviwed
Scientific journal, English - Mirror magneto-optical trap using circularly polarized light-emitting optical fibers
Masaharu Hyodo; Kazuyuki Nakayama; Ryuzo Ohmukai; Kazuyoshi Kurihara; Masayoshi Watanabe
APPLIED OPTICS, OPTICAL SOC AMER, 45, 15, 3629-3633, May 2006, Peer-reviwed, A fiber-optic mirror magneto-optical trap (mirror-MOT) that uses a pair of circularly polarized light-emitting optical fibers as an optical access is demonstrated. The fiber is fabricated so that a length of birefringence fiber, designed to be a quarter wave retarder at both wavelengths of 780 and 852 nm, is attached directly onto a polarization-maintaining normal fiber. The polarization states of light emitted from the fibers are sufficiently circular for the operation of a mirror-MOT with Rb-87 atoms. The mirror-MOT is able to capture approximately the same number of atoms obtainable with a conventional mirror-MOT. The technique makes it possible to fabricate a compact MOT apparatus by introducing the optical fibers directly into an ultrahigh-vacuum chamber. (c) 2006 Optical Society of America
Scientific journal, English - Multiple frequency stabilization of lasers using double saturation spectroscopy
K. Nakayama; M. Hyodo; R. Ohmukai; M. Watanabe
Opt. Commun., 259, 242-250, 2005, Peer-reviwed
Scientific journal, English - Beat-signal synchronization for optical generation of millimeter-wave signals
Masaharu Hyodo; Kazi Sarwal Abedin; Noriaki Onodera; Masayoshi Watanabe
Electron. Lett., 39, 2004, 2004, Peer-reviwed
Scientific journal, English - Emission from planar defect modes excited with surface modes in three-dimensional photonic crystals
Masaru Iida; Masahiko Tani; Kiyomi Sakai; Masayoshi Watanabe; Shin'ichi Katayama; Hirotaka Kondo; Hideaki Kitahara; Seiji Kato; Mitsuo Wada Takeda
Phys. Rev. B, 69, 245119, 2004, Peer-reviwed
Scientific journal, English - Harmonic synchronization of Fourier-synthesized optical pulses to an external optical clock
Masaharu Hyodo; Kazi Sarwal Abedin; Noriaki Onodera; Masayoshi Watanabe
IEEE Photonics Technology Letters, 16, 281, 2004, Peer-reviwed
Scientific journal, English - Calibration free terahertz imaging based on 2D electro-optic sampling technique
M Usami; R Fukasawa; M Tani; M Watanabe; K Sakai
ELECTRONICS LETTERS, IEE-INST ELEC ENG, 39, 24, 1746-1747, Nov. 2003, Peer-reviwed, A two-dimensional electro-optic sampling technique with polarity modulation for THz imaging is proposed and demonstrated. The polarity modulation greatly improves the signal linearity to the THz field. Combining this technique with software lock-in detection, it is found that the modulation efficiency is also improved compared to conventional optical chopping.
Scientific journal, English - A novel technique for optical generation of millimeter-wave signals using multiple phase-locked lasers
M Hyodo; M Watanabe
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E86C, 7, 1236-1244, Jul. 2003, Peer-reviwed, A new technique for optical generation of high-purity millimeter-wave (mm-wave) signals-namely, by synthesizing the outputs from cascadingly phase-locked multiple semiconductor lasers-was developed. Firstly, a high-spectral-purity mm-wave signal was optically generated by heterodyning the outputs from two phase-locked external-cavity semiconductor lasers. The beat signal was detected by a p-i-n photodiode whose output was directly coupled to a coax-waveguide converter followed by a W-band harmonic mixer. By constructing an optical phase-locked loop (OPLL), a high-spectral-purity mm-wave signal with an electrical power of 2.3 muW was successfully generated at 110 GHz with an rms phase fluctuation of 57 mrad. Secondly, the frequency of the mm-wave signal was extended by use of three cascadingly phase-locked semiconductor lasers. This technique uses a semiconductor optical amplifier (SOA) to generate four-wave-mixing (FWM) signals as well as to amplify the input signals. When the three lasers were appropriately tuned, two pairs of FWM signals were nearly degenerated. By phase-locking the offset frequency in one of the nearly degenerated pairs, the frequency separations among the three lasers were kept at a ratio of 1:2. Thus, we successfully generated high-purity millimeter-wave optical-beat signals at frequencies at 330.566 GHz with an rms phase fluctuation of 0.38 rad. A detailed analysis of the phase fluctuations was carried out on the basis of measured power spectral densities. The possibility of extending the mm-wave frequency up to 1 THz by using four cascadingly phase-locked lasers was also discussed.
Scientific journal, English - Atom lithography with ytterbium beam
R. Ohmukai; S. Urabe; M. Watanabe
Appl. Phys. B, 77, 415, 2003, Peer-reviwed
Scientific journal, English - Laser cooling and isotope-shift measurement of Zn+ with 202-nm ultraviolet coherent light laser
M. Matsubara; U. Tanaka; H. Imajo; S. Urabe; M. Watanabe
Appl. Phys. B, 76, 209, 2003, Peer-reviwed
Scientific journal, English - A Compact 209-nm Deep UV cw Light Source for Spectroscopy Using Frequency Doubling of a Diode Laser
Tomoo NISHIMURA; Kenji TOYODA; Masayoshi; WATANABE; Shinji URABE
Jpn. J. Appl. Phys., 45, 5079, 2003
Scientific journal, English - Optical generation on millimeter-wave signals up to 330 GHz by means of cascadingly phase locking three semiconductor lasers
M. Hyodo; M. Watanabe
IEE Photon. Technol. Lett., 15, 458, 2003, Peer-reviwed
Scientific journal, English - Stabilization of a 729-nm laser diode for high-resolution spectroscopy of calcium ions
K. Toyoda; Y. Kawasaki; T. Ikeda; M. Watanabe; S. Urabe
IEICE Transactions on Electronics, E85-C, 165-166, 2003, Peer-reviwed
Scientific journal, English - Optical generation of millimetre-wave signals up to 110 GHz by phase-locking of two external-cavity semiconductor lasers
M Hyodo; M Watanabe
ELECTRONICS LETTERS, IEE-INST ELEC ENG, 38, 25, 1679-1680, Dec. 2002, Peer-reviwed, High-spectral-purity millimetre-wave signals were optically generated by heterodyning the outputs from two phase-locked external-cavity semiconductor lasers. Beat signals were detected by a conventional pin photodiode used as a W-band photoreceiver. A 110-GHz millimetre-wave signal was successfully generated with rms phase fluctuation of 57 mrad.
Scientific journal, English - An electronic read-out circuit for time-domain terahertz imaging with photoconductive antennas
M Herrmann; M Tani; M Watanabe; K Sakai
PHYSICS IN MEDICINE AND BIOLOGY, IOP PUBLISHING LTD, 47, 21, 3711-3718, Nov. 2002, Peer-reviwed, We have developed a signal amplifier for the detection of weak repetitive pulsed signals superimposed on a large back-round. It is based on a double gated integrator principle with two channels locked to a sequence of alternate signal and back-round pulses. The circuit is compact and cost effective, and thus suitable for use in large numbers with detector arrays, for example in terahertz imaging. The performance was verified in terahertz time-domain C spectroscopy based on an amplified femosecond laser and found to be better than that of a commercial lock-in amplifier.
Scientific journal, English - Terahertz imaging of objects in powders
M Herrmann; M Tani; M Watanabe; K Sakai
IEE PROCEEDINGS-OPTOELECTRONICS, IEE-INST ELEC ENG, 149, 3, 116-120, Jun. 2002, Peer-reviwed, The use of terahertz radiation for detecting and imaging objects hidden in powders is demonstrated. Glass, eggshell and various plastics have been imaged in powders such as wheat flour, tale and sugar. The method may have applications in quality control. The images have been compiled by making use of various features of the terahertz; time-domain waveforms. Details arising from refraction and interference close to the resolution limit are discussed. A simple method is suggested for distinguishing between objects of different materials even if their thickness is unknown. The potential of THz radiation for measuring the local density profile of powders is also demonstrated.
Scientific journal, English - Development of a tunable 209 nm continuous-wave light source using two-stage frequency doubling of a Ti : sapphire laser
H Yamamoto; K Toyoda; K Matsubara; M Watanabe; S Urabe
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, INST PURE APPLIED PHYSICS, 41, 6A, 3710-3713, Jun. 2002, We have developed an all-solid-state tunable continuous-wave coherent light source near 209 nm using two-stage frequency doubling of a Ti:sapphire laser. Two-stage frequency doubling was carried out with two enhancement cavities. A 209 nm output power of 100 muW was obtained with a single beta-BaB2O4(BBO) crystal in the doubling. Compensation of the walk-off of the 209 nm radiation was also performed with two BBO crystals and an output power of 310 muW was obtained, The light source described here can be used satisfactorily for spectroscope in the deep ultraviolet region.
Scientific journal, English - Classical and quantum properties of optical parametric amplifier/deamplifier
Y Zhang; K Kasai; M Watanabe
PHYSICS LETTERS A, ELSEVIER SCIENCE BV, 297, 1-2, 29-36, May 2002, Peer-reviwed, The classical gain and the variances of coupled, signal and idler modes of output from continuous nondegenerate optical parametric amplifier are theoretically analyzed under parametric amplification and deamplification conditions. The correlation between the signal and idler modes is also discussed. The results provide design references for nonclassical light generation systems. (C) 2002 Elsevier Science B.V. All rights reserved.
Scientific journal, English - Investigation of the photon-number statistics of twin beams by direct detection
Y. Zhang; K. Kasai; M. Watanabe
Opt. Lett., 27, 1244, 2002, Peer-reviwed
Scientific journal, English - Photoconductive twin dipole antennas for THz transceiver
M Tani; M Watanabe; K Sakai
ELECTRONICS LETTERS, IEE-INST ELEC ENG, 38, 1, 5-6, Jan. 2002, Peer-reviwed, A THz transceiver using twin photoconductive dipole antennas fabricated on the same substrate chip has been demonstrated. With reduced photoconductive noise compared to that of a single photoconductive transceiver, signal-to-noise operation as good as that of a conventional separate emitter-receiver system was achieved. An interference effect due to the adjacent antennas was also observed.
Scientific journal, English - Fourier Synthesis of Stable Ultrafast Optical-Pulse Trains Using Three Lasers and an SOA
Masaharu HYODO; Kazi Sarwar; ABEDIN・Noriaki ONODERA・Kamal; K. GUPTA; Masayoshi WATANABE
Japanese Journal of Applied Physics, 42, 1268-1271, 2002, Peer-reviwed
Scientific journal, English - High-resolution atomic channeling using velocity-selected atomic beam
R Ohmukai; S Urabe; M Watanabe
APPLIED PHYSICS B-LASERS AND OPTICS, SPRINGER-VERLAG, 73, 7, 647-651, Nov. 2001, Peer-reviwed, High-resolution atomic channeling using velocity-controlled atoms may be able to overcome precision limitations of the conventional atom lithography. We have experimentally clarified the dependence of line width and contrast of atomic patterns in the channeling region on the velocity spread of the atomic source for the first time. Thermal or velocity-selected atomic beams prepared with a one-dimensional magneto-optical trap were employed as the atomic sources. We investigated the channeling characteristics by measuring the frequency shifts of the atomic absorption spectra in an intense standing wave light field. As a result., we can show that narrower line width and higher contrast atomic patterns are obtained as the velocity spread becomes narrower. An atomic pattern with an estimated line width of 57 nm was generated when the velocity spread of the atomic source was almost 50 m/s, that is, 1/6 that of the thermal beam.
Scientific journal, English - Laser cooled calcium ions by using ultraviolet laser diode: Significant induction of electron-shelving transition
K. Toyoda; A. Miura; H. Hayasaka・M; Watanabe・S. Urabe
Optics Letters, 26, 1897-1899, 2001, Peer-reviwed
Scientific journal, English - Motional resonances of sympathetically cooled 44Ca+, Zn+ and Ga+ in a linear Paul trap
Y. Kai; K. Toyoda; M.Watanabe; S.Urabe
Japanese Journal of Applied Physics, 40, 5136-5140, 2001, Peer-reviwed
Scientific journal, English - Separation of laser-cooled 42Ca+ and 44Ca+ in a linear Paul trap
K. Toyoda; H. Kataoka; Y. Kai; A. Miura・M; Watanabe・S. Urabe
Applied Physics B, 72, 327-330, 2001, Peer-reviwed
Scientific journal, English - Laser Cooling of Ca+ with an External-Cavity Ultraviolet Diode Laser
H. Hayasaka; S. Urabe・M. Watanabe
Japanese Journal of Applied Physics, 39, L687-L689, 2000, Peer-reviwed
Scientific journal, English - Atomic beam guide by a one-dimensional magneto-optical trap
R Ohmukai; S Urabe; M Watanabe
APPLIED PHYSICS B-LASERS AND OPTICS, SPRINGER VERLAG, 69, 2, 123-128, Aug. 1999, Peer-reviwed, An atomic beam has been collimated, compressed, and deflected simultaneously by an atomic beam guide based on an inclined one-dimensional magneto-optical trap (1D-MOT). Isotope-selected rubidium atoms were extracted from the naturally-mixed thermal atomic beam with this method, We could manipulate the transverse displacement of the deflected beam precisely by adjusting the current in the copper rods to generate the quadrupole magnetic field. We could extract more than 50% of the incident atoms as a deflection beam when we combined this deflection technique with the atomic deceleration using a broadband spectral light.
Scientific journal, English - An all-solid-state light source for generation of tunable continuous-wave coherent radiation around 202 nm
K. Matsubara; U. Tanaka; H. Imajo・M; Watanabe・S. Urabe
Journal of Optical Society of America B, 16, 1668-1671, 1999, Peer-reviwed
Scientific journal, English - Submilliwatt continuous-wave coherent light generation near 214.5 nm by two-stage frequency doubling of a diode laser
K Matsubara; U Tanaka; H Imajo; M Watanabe; S Urabe
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, JAPAN SOC APPLIED PHYSICS, 37, 9A, 4838-4839, Sep. 1998, Peer-reviwed, We generated 0.64 mW of continuous-wave coherent light near 214.5 nm by using an all-solid-state light source. In this source, IR light from a master-laser and power-amplifier system based on diode lasers was frequency-quadrupled in two successive frequently-doubling stages. A continuous frequency-scanning range of more than 7 GHz was observed in the 214-215 nm wavelength region.
Scientific journal, English - Observation of Doppler sidebands of a laser-cooled Ca+ ion by using a low-temperature-operated laser diode
S Urabe; M Watanabe; H Imajo; K Hayasaka; U Tanaka; R Ohmukai
APPLIED PHYSICS B-LASERS AND OPTICS, SPRINGER VERLAG, 67, 2, 223-227, Aug. 1998, Peer-reviwed, The 729-nm radiation obtained from a commercially available laser diode operated at a low temperature was used to observe the S-1/2 - D-5/2 electric-quadrupole-allowed transitions of a laser-cooled Caf ion in a small rf trap. The electron shelving method was used to measure the absorption spectrum of the electric-quadrupole-allowed transitions, and the motional sidebands due to the secular motion of the ion in the harmonic potential well of the rf trap were completely resolved. The effective temperature of the ion, estimated by comparing the observed sideband intensities with the theoretical ones, was less than 4.4 mK. This result is in good agreement with that obtained from the analysis of the linewidth measurement.
Scientific journal, English - An all-solid-state tunable 214.5-nm continuous-wave light source by using two-stage frequency doubling of a diode laser
K Matsubara; U Tanaka; H Imajo; K Hayasaka; R Ohmukai; M Watanabe; S Urabe
APPLIED PHYSICS B-LASERS AND OPTICS, SPRINGER VERLAG, 67, 1, 1-4, Jul. 1998, Peer-reviwed, Tunable 214.5-nm continuous-wave coherent radiation has been generated by using an all-solid-state light source system. The light source consists of the oscillator and amplifier system based on laser diodes and the two-stage frequency doubling system with KNbO3 and beta-BaB2O4 crystals. The power of the generated 214.5-nm light amounts to more than 100 mu W. This light source will be used for laser cooling of Cd+ ions.
Scientific journal, English - Deflection of a velocity compressed Yb atomic beam by a multi-mode spectral laser
M Watanabe; R Ohmukai; U Tanaka; K Hayasaka; H Imajo; S Urabe
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, JAPAN J APPLIED PHYSICS, 36, 12A, 7189-7193, Dec. 1997, Peer-reviwed, We have generated a continuous, monovelocity Yb atomic beam based on a technique combining velocity compression and beam deflection. Two single-mode lasers were used to compress the thermally broadened velocity distribution, and a multi-mode spectrum of a mode-locked laser was used to extract the compressed part as a deflected beam. The observed deflection angles were compared with the calculations. Deflection angles up to 12 degrees were obtained.
Scientific journal, English - Laser cooling and isotope separation of Cd+ ions confined in a linear Paul trap
U Tanaka; H Imajo; K Hayasaka; R Ohmukai; M Watanabe; S Urabe
OPTICS LETTERS, OPTICAL SOC AMER, 22, 17, 1353-1355, Sep. 1997, Peer-reviwed, Cadmium ions in a natural isotope mixture have been trapped in a linear Paul trap and laser cooled. The fluorescence spectra from all even isotopes, including the Cd-108(+) isotopes with a natural abundance of 0.89%, were observed. Additionally, we eliminated the heavier isotopes fi om the trapping region by adjusting the tuning of the laser frequency and by changing the de voltage applied to the end electrodes. (C) 1997 Optical Society of America.
Scientific journal, English - Laser microwave double-resonance experiment on trapped Cd-113(+) ions
U Tanaka; H Imajo; K Hayasaka; R Ohmukai; M Watanabe; S Urabe
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 46, 2, 137-140, Apr. 1997, The possibility of using Cd+ ions as a microwave frequency standard whose light source is all-solid state UV laser system is presented, The ground-state hyperfine splitting of trapped Cd-113(+) ions is measured using an RF trap technique. The transition is detected using a laser microwave double-resonance method in the presence of He buffer gas. The splitting is determined to be 15 199 862 858(2) Hz. The preciseness of the value was improved over that in previous data by seven orders of magnitude. A light source of 214.5 nm is being developed by the authors for optical pumping and laser-cooling of Cd+ ions whose fundamental oscillator is based on diode lasers.
Scientific journal, English - Spatial separation of ion clouds between sympathetically laser-cooled Cd+-ion isotopes in a Penning trap
H Imajo; K Hayasaka; R Ohmukai; U Tanaka; M Watanabe; S Urabe
PHYSICAL REVIEW A, AMERICAN PHYSICAL SOC, 55, 2, 1276-1280, Feb. 1997, Peer-reviwed, Natural Cd+ ions in a Penning trap are cooled sympathetically below 1 K by a Coulomb interaction with directly laser-cooled Be+ ions. Spatial separation of the Be+ and Cd+ ion clouds due to centrifugal force is observed directly. When the frequency of rotation of the ion clouds is accelerated, the separation between Cd+-ion isotopes (A = 110 and 116) can be clearly observed, though their mass difference is very small. The equations of motion for 100 Be+ ions and 50 Cd+ ions are solved to simulate the experiments, and the result shows the spatial separation between the two ion species. The separation between the Cd+-ion isotopes is investigated by comparing the experimental results with numerical calculations.
Scientific journal, English - Isotope-selected measurements of the velocity-controlled Yb atomic beam
R. Ohmukai; H. Imajo; K. Hayasaka; U. Tanaka; M. Watanabe; S. Urabe
Appl. Phys. B, 64, 547-180, 1997, Peer-reviwed
Scientific journal, English - Velocity control of an Yb beam by a frequency-doubled mode-locked laser
M Watanabe; R Ohmukai; U Tanaka; K Hayasaka; H Imajo; S Urabe
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS, OPTICAL SOC AMER, 13, 11, 2377-2381, Nov. 1996, Peer-reviwed, An ytterbium atomic beam has been decelerated with the use of a multimode light beam based on a frequency-doubled mode-locked Ti:sapphire laser. Compression of the atomic velocity distribution was achieved by the addition of a copropagating single-mode light beam. The contribution of each isotope to the observed compressed peaks of the velocity distribution is explained. (C) 1996 Optical Society of America.
Scientific journal, English - Determination of the ground-state hyperfine splitting of trapped Cd-113(+) ions
U Tanaka; H Imajo; K Hayasaka; R Ohmukai; M Watanabe; S Urabe
PHYSICAL REVIEW A, AMERICAN PHYSICAL SOC, 53, 6, 3982-3985, Jun. 1996, Peer-reviwed, The ground-state hyperfine splitting of trapped Cd-113(+) ions has been measured to be 15 199 862 858(2) Hz. The transition was detected by a laser microwave double-resonance method in the presence of He buffer gas. The result was corrected for the second-order magnetic-field dependence. This paper also discusses the possibility of using Cd+ ions as a microwave-frequency standard.
Scientific journal, English - High-resolution Ultraviolet Spectra of Sympathetically-laser-cooled Cd+ Ions
H. Imajo; K; Hayasaka・R. Ohmukai; U. Tanaka・M; Watanabe・S. Urabe
Physical Review A, 53, 22-125, Jan. 1996, Peer-reviwed
Scientific journal, English - OBSERVATION OF LASER-COOLED BE+-ION CLOUDS IN A PENNING TRAP
H IMAJO; K HAYASAKA; R OHMUKAI; M WATANABE; S URABE
APPLIED PHYSICS B-LASERS AND OPTICS, SPRINGER VERLAG, 61, 3, 285-289, Sep. 1995, Peer-reviwed, Be+ ions trapped in a Penning trap are laser-cooled to about 10 mK. The excitation spectra of ion clouds containing about 500 ions are obtained by scanning the frequency of the cooling laser and discontinuities in these spectra are observed because of phase transitions. When the cooled ions are heated electrically by applying an rf voltage, no phase transition occurs and the spectra become continuous. Two-dimensional measurement of the ion clouds is carried out and the abrupt change in the shape of the ion cloud due to the phase transition is observed, When many ions are trapped and cooled, the phase transition occurs partially and a transient state where two states are mixed can be observed. The static properties of the ions are also measured by using an additional probe laser and the results of experimental measurements are compared with theoretical predictions.
Scientific journal, English - High-power second harmonic generation with picosecond and hundred-picosecond pulses of a cw mode-locked Ti:sapphire laser
M. Watanabe; K; Hayasaka・H. Imajo; R. Ohmukai; S. Urabe
Optics Letters, 19, 637-639, May 1994, Peer-reviwed
Scientific journal, English - TUNABLE-397-NM LIGHT-SOURCE FOR SPECTROSCOPY OBTAINED BY FREQUENCY-DOUBLING OF A DIODE-LASER
K HAYASAKA; M WATANABE; H IMAJO; R OHMUKAI; S URABE
APPLIED OPTICS, OPTICAL SOC AMER, 33, 12, 2290-2293, Apr. 1994, Peer-reviwed, Continuous-wave radiation of 1.8 mW at 397 nm was generated by frequency doubling a 100-mW GaAlAs diode laser in a lithium iodate crystal placed in an external enhancement cavity. The radiation had a narrow linewidth and a continuous frequency-scanning range of 6 GHz. The UV radiation obtained was applied to laser cooling of calcium ions stored in a rf trap.
Scientific journal, English - SUM-FREQUENCY GENERATION NEAR 194-NM WITH AN EXTERNAL-CAVITY BY SIMULTANEOUS ENHANCEMENT OF FREQUENCY-STABILIZED FUNDAMENTAL LASERS
M WATANABE; K HAYASAKA; H IMAJO; R OHMUKAI; S URABE
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, JAPAN J APPLIED PHYSICS, 33, 3B, 1599-1602, Mar. 1994, Peer-reviwed, Continuous-wave coherent radiation near 194 nm has been generated by sum-frequency mixing with simultaneous enhancement of both fundamental lasers. An output power of 31 muW was obtained at 194 nm. The frequency of a Ti: sapphire laser, which was used as one of the fundamental lasers, was stabilized with a frequency fluctuation of 80 kHz rms by using a mode-interference method.
Scientific journal, English - DOPPLER-FREE OPTOGALVANIC SPECTROSCOPY OF CA+ AND CA
R OHMUKAI; M WATANABE; H IMAJO; K HAYASAKA; S URABE
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, JAPAN J APPLIED PHYSICS, 33, 1A, 311-314, Jan. 1994, Peer-reviwed, The high-resolution Doppler-free optogalvanic spectra of Ca+ and Ca were observed using a commercial hollow-cathode lamp and a single-mode cw ring Ti:sapphire laser or a dye laser. The measured full width at half-intensity-maximum (FWHM) of the Ca+ Doppler-free component was 167 MHz, which is sufficient for calibrating the wavelength for the laser cooling of Ca+ ions. The amount of collision broadening in the Ca+ spectrum was much greater than that in the Ca spectrum.
Scientific journal, English - Tunable 397 nm light source for laser cooling of ca ions based on frequency doubling of diode laser
Kazuhiro Hayasaka; Masayoshi Watanabe; Hidetsnka Imajo; Ryuzo Ohmukai; Shinji Urabe
Japanese Journal of Applied Physics, 33, 3 S, 1595-1598, 1994, Peer-reviwed, We have fabricated an rf ion trap and laser-cooling light sources to observe shelving transition in a single calcium ion. All the radiation required for laser cooling and observation of the transition can be prepared with diode lasers in this system. Continuous-wave radiation at 397 nm for laser cooling was generated by frequency doubling of a GaAlAs laser in an external enhancement cavity. As a preliminary experiment for observing the shelving transition, laser cooling of one hundred calcium ions was demonstrated using this radiation and another diode laser. © 1994 Japanese Journal of applied Physics. All Rights Resereved.
Scientific journal, English - Laser cooling of ca+ ions and observation of collision effects
Shinji Urabe; Kazuhiro Hayasaka; Masayoshi Watanabe; Hidetsuka Imajo; Ryuzo Ohmukai
Japanese Journal of Applied Physics, 33, 3 S, 1590-1594, 1994, Peer-reviwed, This paper describes our recent experimental results on trapping and laser cooling of Ca+ ions. The measurement of the characteristics of laser-cooled Ca+ ions in an rf quadrupole ion trap, such as the fluorescence line shape and phase transition, is described. Observation of two types of collision-induced “quantum jumps” of a Ca+ ion in a background gas of H2 or air is also described. Since the rate of the collision-induced jumps is very high for Ca+, it is necessary to achieve an extremely high vacuum condition for frequency standard applications. © 1994 Japanese Journal of applied Physics. All Rights Resereved.
Scientific journal, English - LASER COOLING OF A SINGLE CA+ ION - OBSERVATION OF QUANTUM JUMPS
S URABE; K HAYASAKA; M WATANABE; H IMAJO; R OHMUKAI; R HAYASHI
APPLIED PHYSICS B-PHOTOPHYSICS AND LASER CHEMISTRY, SPRINGER VERLAG, 57, 5, 367-371, Nov. 1993, Peer-reviwed, This paper describes trapping and laser cooling of a Ca+ ion in an rf quadrupole ion trap. A single Ca+ ion is laser cooled to below 130 mK and quantum jumps are observed by exciting the ion into the metastable D5/2 state via the P3/2 state. The lifetime of the metastable D5/2 state is estimated from the distribution of the dark periods of the quantum-jump signal. Collision-induced jumps between the metastable D3/2 state and the D5/2 state in a background gas are also directly observed.
Scientific journal, English - Cooling of a Small Number of Be+ Ions in a Penning Trap
H. Imajo; S. Urabe; K. Hayasaka・M; Watanabe・R. Hayashi
Applied Physics B, 57, 141-144, Aug. 1993, Peer-reviwed
Scientific journal, English - CONTINUOUS-WAVE SUM-FREQUENCY GENERATION NEAR 194 NM WITH A COLLINEAR DOUBLE ENHANCEMENT CAVITY
M WATANABE; K HAYASAKA; H IMAJO; S URABE
OPTICS COMMUNICATIONS, ELSEVIER SCIENCE BV, 97, 3-4, 225-227, Mar. 1993, Peer-reviwed, A double resonant cavity for sum-frequency generation has been successfully operated; it accomodates a walk-off-compensated configuration of beta-BaB2O4 crystals with collinear circulation of the fundamental beams. Continuous-wave 194 nm coherent radiation has been obtained with an output power of 31 muW.
Scientific journal, English - CONTINUOUS-WAVE SUM-FREQUENCY GENERATION NEAR 194 NM WITH A COLLINEAR DOUBLE ENHANCEMENT CAVITY
M WATANABE; K HAYASAKA; H IMAJO; S URABE
OPTICS COMMUNICATIONS, ELSEVIER SCIENCE BV, 97, 3-4, 225-227, Mar. 1993, Peer-reviwed, A double resonant cavity for sum-frequency generation has been successfully operated; it accomodates a walk-off-compensated configuration of beta-BaB2O4 crystals with collinear circulation of the fundamental beams. Continuous-wave 194 nm coherent radiation has been obtained with an output power of 31 muW.
Scientific journal, English - Laser Cooling of a Single Ca+ Ion: Observation of Quantum Jumps
S. Urabe; K. Hayasaka; M. Watanabe; H. Imajo; R. Ohmukai; R. Hayashi
Appl. Phys. B, 57, 367, 1993
Scientific journal, English - Continuous-wave sum-frequency generation near 194 nm with a collinear double enhancement cavity
M.Watanabe; K.Hayasaka; H.Imajo; S. Urabe
Opt. Commun, 97, 225, 1993, Peer-reviwed
Scientific journal, English - CONTINUOUS-WAVE SUM-FREQUENCY GENERATION NEAR 194 NM IN BETA-BAB2O4 CRYSTALS WITH AN ENHANCEMENT CAVITY
M WATANABE; K HAYASAKA; H IMAJO; S URABE
OPTICS LETTERS, OPTICAL SOC AMER, 17, 1, 46-48, Jan. 1992, Peer-reviwed, Continuous-wave coherent radiation tunable near 194 nm has been generated by sum-frequency generation in beta-BaB2O4 placed inside an external enhancement cavity. An output power of 16-mu-W has been obtained with a walk-off-compensated configuration of beta-BaB2O4 crystals.
Scientific journal, English - CONTINUOUS-WAVE SUM-FREQUENCY GENERATION NEAR 194 NM IN BETA-BAB2O4 CRYSTALS WITH AN ENHANCEMENT CAVITY
M WATANABE; K HAYASAKA; H IMAJO; S URABE
OPTICS LETTERS, OPTICAL SOC AMER, 17, 1, 46-48, Jan. 1992, Continuous-wave coherent radiation tunable near 194 nm has been generated by sum-frequency generation in beta-BaB2O4 placed inside an external enhancement cavity. An output power of 16-mu-W has been obtained with a walk-off-compensated configuration of beta-BaB2O4 crystals.
Scientific journal, English - Measurements of Motional Frequencies for Laser-cooled Ions in a Penning Trap
H. Imajo; S. Urabe; K. Hayasaka; M. Watanabe
J. Mod. Opt, 39, 317, 1992, Peer-reviwed
Scientific journal, English - Laser cooling of trapped Ca+ and measurement of the 3 2D5/2 state lifetime
S. Urabe; M. Watanabe; H. Imajo; K. Hayasaka
Opt. Lett., 17, 1140, 1992, Peer-reviwed
Scientific journal, English - Optical detection of stored Ca+ ions by two solid state lasers
S. Urabe; H. Imajo; K. Hayasaka; M. Watanabe
J. Mod. Opt., 39,, 417, 1992, Peer-reviwed
Scientific journal, English - Continuous-wave sum-frequency generation near 194 nm in β-BaB２O４ crystals with an enhancement cavity
M.Watanabe; K.Hayasaka; H.Imajo; S. Urabe
Opt. Lett, 17, 46, 1992, Peer-reviwed
Scientific journal, English - Generation of continuous-wave coherent radiation tunable &0d0a;down to 190.8 nm in beta-BaB↓2」O↓4」
Applied Physics B, 53, 11-13, 1991, Peer-reviwed
Scientific journal, English - Generation of continuous-wave coherent radiation tunable &0d0a;down to 190.8 nm in β-BaB↓2」O↓4」
Applied Physics B, 53, 11-13, 1991, Peer-reviwed
Scientific journal, English - Trapping of Ca+ ions and optical detection
S. Urabe; H. Imajo; K. Hayasaka; M. Watanabe
Jpn. J. Appl. Phys., 30, 1532, 1991
Scientific journal, English - Generation of Continuous-Wave Coherent Radiation Tunable Down to 190.8nm in β-BaB２O４
M.Watanabe; K.Hayasaka; H.Imajo; S. Urabe
Appl. Phys. B, 53,, 11, 1991, Peer-reviwed
Scientific journal, English - Coherent Soft X-ray Generation by the Harmonics of an Ultrahigh-Power KrF Laser
N. Sarukura; K. Hata; T. Adachi; R. Nodomi; M. Watanabe; S. Watanabe
Phys. Rev. A, 43, 1669, 1991, Peer-reviwed
Scientific journal, English - High Repetition Rate, Wide-Aperture KrF Lasers for Subpicosecond Amplification
R. Nodomi; Y. Oheda; K. Sajiki; S. Nakajima; M. Watanabe; S. Watanabe
J. Quantum. Electron, 27, 441, 1991, Peer-reviwed
Scientific journal, English - HIGH-REPETITION-RATE TERAWATT EXCIMER LASER SYSTEM WITH GATED GAIN AMPLIFICATION
M WATANABE; K HATA; T ADACHI; R NODOMI; S WATANABE
OPTICS LETTERS, OPTICAL SOC AMER, 15, 15, 845-847, Aug. 1990, Peer-reviwed
Scientific journal, English - Nonlinear Process in UV Optical Material at 248nm
K. Hata; M. Watanabe; S. Watanabe
Appl. Phys. B, 50, 55, 1990, Peer-reviwed
Scientific journal, English - Multiterawatt excimer laser system
S. Watanabe; A. Endoh; M. Watanabe; N. Sarukura; K. Hata
J. Opt. Soc. Am. B, 6, 1989, Peer-reviwed
Scientific journal, English - Multiterawatt subpicosecond KrF laser
A. Endoh; M. Watanabe; N. Sarukura; S. Watanabe
Opt. Lett., 14, 353, 1989, Peer-reviwed
Scientific journal, English - Subpicosecond UV Pulse Generation for a Multiterawatt KrF Laser
M. Watanabe; A. Endoh; N. Sarukura; S. Watanabe
Appl. Phys. B, 48, 417, 1989, Peer-reviwed
Scientific journal, English - Property of Amplified Spontaneous Emission and Saturable Absorber for a Terawatt XeCl Laser
M. Watanabe; A. Endoh; N. Sarukura; S. Watanabe
J. Appl. Phys., 65, 428, 1989, Peer-reviwed
Scientific journal, English - Terawatt XeCl discharge laser system
S. Watanabe; A. Endoh; M. Watanabe; N. Sarukura
Opt. Lett., 13, 580, 1988, Peer-reviwed
Scientific journal, English - DEVELOPMENT OF AN ELECTRON-BEAM-PUMPED HIGH-POWER KRF LASER AS A SHORT-PULSE AMPLIFIER
A ENDOH; M WATANABE; S WATANABE
FUSION TECHNOLOGY, AMER NUCLEAR SOCIETY, 11, 3, 492-496, May 1987, Peer-reviwed
Scientific journal, English - Picosecond amplification in wide-aperture KrF lasers
A. Endoh; M. Watanabe; S. Watanabe
Opt. Lett., 12, 906, 1987, Peer-reviwed
Scientific journal, English - High repetition long pulse XeCl laser with a coaxial ceramic pulse-forming line
S. Watanabe; M. Watanabe; A. Endoh; T. Sato
Rev. Sc. Instru., 57, 2970, 1986, Peer-reviwed
Scientific journal, English - Single Picosecond UV Pulse Generation by Mode-Locking of an Excimer Laser-Pumped Dye Laser
M. Watanabe; A. Endoh; S. Watanabe
Appl. Phys. B, 41, 49, 1986, Peer-reviwed
Scientific journal, English - Single Picosecond UV Pulse Generation by Mode-Locking of an Excimer Laser-Pumped Dye Laser
M. Watanabe; A. Endoh; S. Watanabe
Appl. Phys. B, 41, 49, 1986, Peer-reviwed
Scientific journal, English - Development of a low impedance electron-beam system for high power excimer laser excitation.
A. Endoh; M. Watanabe; S. Watanabe
Proceedings of the 5th IEEE Pulsed Power Conference, 5, 1985, Peer-reviwed
International conference proceedings, English - An electrically triggered 200kV rail-gap switch for wide aperture excimer lasers
A. Endoh; S. Watanabe; M. Watanabe
Appl. Phys., 55, 1332, 1984, Peer-reviwed
Scientific journal, English - Mode locking of excimer laser pumped dye laser
M. Watanabe; S. Watanabe; A. Endoh
Appl. Phys. Lett., 45, 929, 1984, Peer-reviwed
Scientific journal, English - Passive mode locking of a long pulse XeCl laser
S. Watanabe; M. Watanabe; A. Endoh
Appl. Phys. Lett., 43, 533, 1983, Peer-reviwed
Scientific journal, English - Generation of a 300-psec pulse by direct mode locking of a long-pulse XeCl laser
M. Watanabe; S. Watanabe; A. Endoh
Opt. Lett., 8, 638, 1983, Peer-reviwed
Scientific journal, English
Lectures, oral presentations, etc.
- Interferometric measurement of a biphoton state with continuous-variables by homodyne detection
Yashuai Han; Daohua Wu; Katsuyuki Kasai; Masayoshi Watanabe; Yun Zhang
Oral presentation, English, 第66回応用物理学会春季学術講演会, Domestic conference
Mar. 2019 - Multi-photon interference between a two-photon state and a weak coherent state
Yun Zhang; Lirong Wang; Masayoshi Watanabe
Oral presentation, English, The International Photonics and Optoelectronics, International conference
31 Oct. 2018 - Generation of millimeter-wave signals by phase-locking of two longitudinal modes of laser using FPGA
Toru Asaka; Masayoshi Watanabe; Shingo Saito; Masaharu Hyodo
Poster presentation, English, OPJ2017, International conference
01 Nov. 2017 - Observation of two-photon interference for continuous variables with homodyne detection
Daohua WU; Kota Kawamoto; K. Kasai; M. Watanabe; Y. Zhang
Oral presentation, English, The 24th Congress of the International Commission for Optics, Domestic conference
24 Aug. 2017 - Optimization of Power Spectral Density and Polarization Compensation for Coherence-Selectable ECDL
Masaharu Hyodo; Akira Kawakami; Shingo Saito; Masayoshi Watanabe; Takahiro Kubo; Masaaki Adachi
Oral presentation, English, The 25th International Semiconductor Laser Conference, International conference
14 Sep. 2016 - Demonstration of coherence-selectable operation of external-cavity semiconductor laser
Masaharu Hyodo; Akira Kawakami; Shingo Saito; Masayoshi Watanabe; Yuki Tamura; Masaaki Adachi
Oral presentation, English, The 4th Advanced Lasers and Photon Sources (ALPS’15), International conference
24 Apr. 2015
Courses
- 総合コミュニケーション科学
The University of Electro-Communications - 総合コミュニケーション科学
電気通信大学 - 先進理工学基礎
The University of Electro-Communications - 先進理工学基礎
電気通信大学 - 量子エレクトロニクス
The University of Electro-Communications - 量子エレクトロニクス
電気通信大学 - 光・量子エレクトロニクス基礎
The University of Electro-Communications - 光・量子エレクトロニクス基礎
電気通信大学 - 基礎電磁気および演習
The University of Electro-Communications - 基礎電磁気および演習
電気通信大学