Papers - Ota, Yasutomo

量子光回路応用に向けた量子ドットのオンチップ光励起の検討

長田有登， 勝見亮太， 角田雅弘， 太田泰友， 岩本敏， 荒川泰彦

応用物理学会学術講演会講演予稿集 第 78 回応用物理学会秋季学術講演会, 863-863 78th 2017

Joint Work

Photoluminescence Properties of GaSb/GaAs Quantum Dots Grown on Ge and GaAs Substrates

Z Zon, S Thainoi, S Kiravittaya, A Tandaechanurat, S Panyakeow, Y Ota, ...

JSAP Annual Meetings Extended Abstracts The 64th JSAP Spring Meeting 2017 …  2017

Joint Work

High-Q Two-dimensional Photonic Crystal Nanocavity on Glass with an Upper

R Kawata, A Fujita, N Pholsen, S Iwamoto, Y Ota

Opt. Express 25, 19981  2017

Joint Work

Control of Circularly Polarized Electromagnetic Field using Chiral Photonic Crystals-Artificial Optical Activity and Control of QD Emission

S Iwamoto, S Takahashi, T Tajiri, Y Ota, Y Arakawa

電子情報通信学会技術研究報告 116 (388 (OPE2016 116-158)), 1-3  2017

Joint Work

Effect of metal side claddings on emission decay rates of single quantum dots embedded in a sub-wavelength semiconductor waveguide

T Yamamoto, Y Ota, S Ishida, N Kumagai, S Iwamoto, Y Arakawa

Japanese Journal of Applied Physics 55 (8S3), 08RC02 (IOP PUBLISHING LTD)  55 ( 8 )  2016

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0021-4922

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We experimentally investigate the emission decay rates of self-assembled single InAs quantum dots (QDs) embedded in sub-wavelength semiconductor waveguides with and without metal side claddings. Compared with as-grown single QDs, we observe a clear suppression (enhancement) in the radiative decay rates of single InAs QDs embedded in the sub-wavelength semiconductor waveguides without (with) metal cladding, respectively. The decay rate for QDs in metal-clad waveguides is similar to 2 times faster than that in waveguides without metal. Numerical calculations using models that include the effects of structural imperfections show good agreement with the experimental results, and reveal that the most important structural imperfection is the gap between the metal and the semiconductor. (C) 2016 The Japan Society of Applied Physics.

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Demonstration of a plasmonic laser using quantum dot gain medium

J Ho, J Tatebayashi, S Sergent, CF Fong, Y Ota, S Iwamoto, Y Arakawa

2016 Compound Semiconductor Week (CSW)[Includes 28th International … (IEEE)   2016

Research paper (scientific journal), Joint Work, Accepted

Control of quantum dot light emission by chiral photonic crystal structures

S Iwamoto, S Takahashi, T Tajiri, Y Ota, Y Arakawa

2016 Progress in Electromagnetic Research Symposium (PIERS), 2572-2572 (IEEE)     2572 - 2572 2016

Research paper (scientific journal), Joint Work, Accepted

Control of Light Polarization using Photonic and Phononic Crystals

S Iwamoto, S Takahashi, I Kim, T Tajiri, Y Ota, Y Arakawa

Asia Communications and Photonics Conference, AS2F. 2 (Asia Communications and Photonics Conference, ACP)  2016-November 2016

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2162-108X

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Photonic and phnonic crystals offer the possibilities of controlling light polarization efficiently. Here, we discuss giant optical rotation in a chiral photonic crystal and enhanced photoelastic modulation in a phononic crystal cavity.

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Advanced nanoscale light sources based on photonic crystal nanocavity quantum dot lasers

Y Ota, S Iwamoto, Y Arakawa

IEICE Technical Report; IEICE Tech. Rep. 116 (372), 9-13 (電子情報通信学会)  116 ( 372 ) 9 - 13 2016

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0913-5685

A nanowire-based plasmonic quantum dot laser

J Ho, J Tatebayashi, S Sergent, CF Fong, Y Ota, S Iwamoto, Y Arakawa

Nano letters 16 (4), 2845-2850 (AMER CHEMICAL SOC)  16 ( 4 ) 2845 - 2850 2016

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1530-6984

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Quantum dots enable strong carrier confinement and exhibit a delta-function like density of states, offering significant improvements to laser performance and high temperature stability when used as a gain medium. However, quantum dot lasers have been limited to photonic cavities that are diffraction-limited and further miniaturization to meet the demands of nanophotonic-electronic integration applications is challenging based on existing designs. Here we introduce the first quantum dot-based plasmonic laser to reduce the cross-sectional area of nanowire quantum dot lasers below the cutoff limit of photonic modes while maintaining the length in the order of the lasing wavelength. Metal organic chemical vapor deposition grown GaAs-AlGaAs core-shell nanowires containing InGaAs quantum dot stacks are placed directly on a silver film, and lasing was observed from single nanowires originating from the InGaAs quantum dot emission into the low-loss higher order plasmonic mode. Lasing threshold pump fluences as low as similar to 120 mu J/cm(2) was observed at 7 K, and lasing was observed up to 125 K. Temperature stability from the quantum dot gain, leading to a high characteristic temperature was demonstrated. These results indicate that high-performance, miniaturized quantum dot lasers can be realized with plasmonics.

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p-shell carrier assisted dynamic nuclear spin polarization in single quantum dots at zero external magnetic field

CF Fong, Y Ota, E Harbord, S Iwamoto, Y Arakawa

Physical Review B 93 (12), 125306  2016

Research paper (scientific journal), Joint Work, Accepted

Position dependent optical coupling between single quantum dots and photonic crystal nanocavities

K Kuruma, Y Ota, M Kakuda, D Takamiya, S Iwamoto, Y Arakawa

Applied Physics Letters 109 (7), 071110 (AMER INST PHYSICS)  109 ( 7 )  2016

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0003-6951

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We demonstrate precise and quick detection of the positions of quantum dots (QDs) embedded in two-dimensional photonic crystal nanocavities. We apply this technique to investigate the QD position dependence of the optical coupling between the QD and the nanocavity. We use a scanning electron microscope (SEM) operating at a low acceleration voltage to detect surface bumps induced by the QDs buried underneath. This enables QD detection with a sub-10 nm precision. We then experimentally measure the vacuum Rabi spectra to extract the optical coupling strengths (gs) between single QDs and cavities, and compare them to the values estimated by a combination of the SEM-measured QD positions and electromagnetic cavity field simulations. We found a highly linear relationship between the local cavity field intensities and the QD-cavity gs, suggesting the validity of the point dipole approximation used in the estimation of the gs. The estimation using SEM has a small standard deviation of 66.2%, which potentially enables the high accuracy prediction of g prior to optical measurements. Our technique will play a key role for deeply understanding the interaction between QDs and photonic nanostructures and for advancing QD-based cavity quantum electrodynamics. Published by AIP Publishing.

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Modulation of Dynamic Nuclear Spin Polarization in Single InAs/GaAs Quantum Dots by Photonic Bandgap Effect

CF Fong, Y Ota, S Iwamoto, Y Arakawa

JSAP Annual Meetings Extended Abstracts, 3086-3086  2016

Joint Work

Demonstration of a three-dimensional photonic crystal nanocavity in a <110>-layered diamond structure

T. Tajiri, S. Takahashi, Y. Ota, J. Tatebayashi, S. Iwamoto, Y. Arakawa

Applied Physics Letters 107 ( 071102 )  2015.08

Research paper (scientific journal), Joint Work, Accepted

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Effect of metal side claddings on emission decay rate of single quantum dots embedded in a subwavelength semiconductor waveguide

Takumi Yamamoto, Yasutomo Ota, Satomi Ishida, Naoto Kumagai, Satoshi Iwamoto, Yasuhiko Arakawa

2015 20TH MICROOPTICS CONFERENCE (MOC) (IEEE)   2015

Research paper (scientific journal), Joint Work, Accepted

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We measured the emission decay rates of self-assembled InAs single quantum dots (QDs) embedded in subwavelength-width semiconductor waveguides with and without Au side claddings. The Au claddings increased the decay rate of single QDs by similar to 2 times, which is consistent with numerical simulations taking account of fabrication imperfection.

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Demonstration of a three-dimensional photonic crystal nanocavity in a⟨ 110⟩-layered diamond structure

T Tajiri, S Takahashi, Y Ota, J Tatebayashi, S Iwamoto, Y Arakawa

Applied Physics Letters 107 (7), 071102  2015

Research paper (scientific journal), Joint Work, Accepted

Circularly polarized light emission of quantum dots at the band edge of three-dimensional chiral photonic crystals

S Takahashi, T Tajiri, Y Ota, J Tatebayashi, S Iwamoto, Y Arakawa

CLEO: QELS_Fundamental Science, FF1C. 2 (IEEE)  2015-August   1551p 2015

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2160-9020

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We demonstrate highly circularly polarized emission from quantum dots in semiconductor chiral photonic crystals. The emission is influenced by the difference in density of states between the orthogonal circular polarizations at the polarization band edge.

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Asymmetric out-of-plane power distribution in a two-dimensional photonic crystal nanocavity

Y Ota, S Iwamoto, Y Arakawa

Optics letters 40 (14), 3372-3375 (OPTICAL SOC AMER)  40 ( 14 ) 3372 - 3375 2015

Research paper (scientific journal), Joint Work, Accepted,  ISSN  0146-9592

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Conventional air-bridge two-dimensional photonic crystal (2D-PhC) nanocavities emit light with an equal power distribution for upward and downward out-of-plane directions. Some applications, however, require concentration of the radiation in a preferred direction. In this Letter, we design a 2D-PhC nanocavity that radiates dominantly into one of the out-of-plane directions with a narrow far-field distribution. Our design is based on a conventional air-bridge L3 photonic crystal nanocavity. The asymmetric out-of-plane power distribution is achieved solely by adding periodic shallow holes on the slab surface, which also function as a second-order grating for the directional beaming. (C) 2015 Optical Society of America

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Influence of the relative positions of quantum dots and nanocavities on the optical coupling strength

K Kuruma, Y Ota, D Takamiya, M Kakuda, S Iwamoto, Y Arakawa

2015 11th Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR) 3, 1-2 (Institute of Electrical and Electronics Engineers Inc.)  3 2015

Research paper (scientific journal), Joint Work, Accepted

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We use scanning electron microscopy to precisely measure the locations of quantum dots buried in photonic crystal nanocavities. We show that well-positioned dots (at the field maximum) can exhibit vacuum Rabi splittings larger than 180μeV.

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Single emitter vacuum Rabi splitting measured through direct free space spontaneous emission

Y Ota, R Ohta, N Kumagai, S Iwamoto, Y Arakawa

2015 Conference on Lasers and Electro-Optics (CLEO), 1-2 (IEEE)  2015-August   1551p 2015

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2160-9020

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We measured the vacuum Rabi splitting of a single quantum emitter through direct free space spontaneous emission. This lays the groundwork for accessing diverse cavity quantum electrodynamics phenomena manifesting themselves only in the spontaneous emission.

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