Papers - Ota, Yasutomo

Growth of high-quality InAs quantum dots embedded in GaAs nanowire structures on Si substrates

Jinkwan Kwoen, Katsuyuki Watanabe, Yasutomo Ota, Satoshi Iwamoto, Yasuhiko Arakawa

Physica Status Solidi (C) Current Topics in Solid State Physics 10 ( 11 ) 1496 - 1499 2013.11

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1862-6351

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We present the growth of InAs quantum dots (QD) embedded in GaAs nanowires (NW) on silicon and demonstrate clear single photon emission. Sharp excitonic emission (linewidth of 162 μeV) and the generation of single photons (g(2)(0) = 0.18) was observed by low temperature photoluminescence measurements, suggesting a high optical quality which can be attributed to the high crystal quality of the QD structure. It is believed that the crystal quality is high due to the Stranski-Krastanov (S-K) mode of the growth. This structure may open new ways for the integration of such photon emitters into future 'on-silicon' quantum optical circuits. © 2013 WILEY-VCH Verlag GmbH &amp
Co. KGaA, Weinheim.

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Electro-mechanical Q factor control of photonic crystal nanobeam cavity

R Ohta, Y Ota, H Takagi, N Kumagai, K Tanabe, S Ishida, S Iwamoto, ...

Japanese Journal of Applied Physics 52 (4S), 04CG01 52 ( 4 )  2013

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

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We design and demonstrate a photonic crystal nanobeam cavity with a Q factor controllable by a micro-electro-mechanical system (MEMS). The cavity is evanescently coupled to an adjacent nanobeam waveguide, and its Q factor is controlled by electro-mechanically adjusting the gap distance between them. We experimentally demonstrate control of the Q factor from 2,250 to 2,750, by applying voltage from 0 to 11 V. © 2013 The Japan Society of Applied Physics.

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Enhancement of valence band mixing in individual InAs/GaAs quantum dots by rapid thermal annealing

E Harbord, Y Ota, Y Igarashi, M Shirane, N Kumagai, S Ohkouchi, ...

Japanese Journal of Applied Physics 52 (12R), 125001 (IOP PUBLISHING LTD)  52 ( 12 )  2013

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

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We measure polarization resolved photoluminescence from excitonic complexes in tens of single InAs/GaAs quantum dots (QDs) over a wide range of energies in two samples: one as-grown, the other subjected to rapid thermal annealing (RTA). thing the linear polarization of the X+ emission as a probe of the valence band mixing (VBM), we find that RTA enhances QD VBM, attributed to the increase in QD height. We complement our measurements with 8-band k . p calculations, which suggest the increase in height on annealing is responsible for this enhancement. (C) 2013 The Japan Society of Applied Physics

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Self-frequency summing in quantum dot photonic crystal nanocavity lasers

Y Ota, K Watanabe, S Iwamoto, Y Arakawa

Applied Physics Letters 103 (24), 243115 103 ( 24 )  2013

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

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Self-frequency summing in photonic crystal nanocavity quantum dot lasers

Yasutomo Ota, Katsuyuki Watanabe, Satoshi Iwamoto, Yasuhiko Arakawa

Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest 103 ( 24 )  2013

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

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Self-frequency summing processes in photonic crystal nanocavity quantum dot lasers are observed. High quality factors and small mode volumes of the nanocavities facilitate efficient nonlinear frequency summing processes, generating a variety of visible emission lines. © 2013 IEEE.

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Self-frequency Summing in Photonic Crystal Nanocavity Quantum Dot Lasers

Yasutomo Ota, Katsuyuki Watanabe, Satoshi Iwamoto, Yasuhiko Arakawa

2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS PACIFIC RIM (CLEO-PR) (IEEE)   2013

Research paper (scientific journal), Joint Work, Accepted

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Self-frequency summing processes in photonic crystal nanocavity quantum dot lasers are observed. High quality factors and small mode volumes of the nanocavities facilitate efficient nonlinear frequency summing processes, generating a variety of visible emission lines.

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Self-frequency Summing in Photonic Crystal Nanocavity Quantum Dot Lasers

Ota Yasutomo, Watanabe Katsuyuki, Iwamoto Satoshi, Arakawa Yasuhiko

2013 CONFERENCE ON LASERS AND ELECTRO-OPTICS PACIFIC RIM (CLEO-PR)  2013

Research paper (scientific journal), Joint Work, Accepted

Self-frequency summing in photonic crystal nanocavity quantum dot lasers

Y Ota, K Watanabe, S Iwamoto, Y Arakawa

Conference on Lasers and Electro-Optics/Pacific Rim, MI2_7  2013

Research paper (scientific journal), Joint Work, Accepted

Observation of enhanced exciton decay rate of single InAs quantum dots in nanoscale metal-semi conductor-metal plasmonic structures

T Yamamoto, Y Ota, E Harbord, S Ishida, N Kumagai, S Iwamoto, ...

2013 International Conference on Solid State Devices and Materials, 1020-1021  2013

Research paper (scientific journal), Joint Work, Accepted

Nonlinear photonics in single quantum dot-photonic crystal nanocavity couples systems

S Iwamoto, Y Ota, H Takagi, N Kumagai, Y Arakawa

Conference on Lasers and Electro-Optics/Pacific Rim, MI2_1 (IEEE)   2013

Research paper (scientific journal), Joint Work, Accepted

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We will present our recent advances on single quantum dot-photonic crystal nanocavity coupled systems. Cavity enhanced two-photon emission and large optical Stark effect with extremely low control power in these systems will be mainly discussed.

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Nanocavity-based self-frequency conversion laser

Y Ota, K Watanabe, S Iwamoto, Y Arakawa

Optics Express 21 (17), 19778-19789 (OPTICAL SOC AMER)  21 ( 17 ) 19778 - 19789 2013

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1094-4087

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Self-frequency conversion (SFC), where both laser oscillation and nonlinear frequency conversion occurs in the same laser crystal, has been used to efficiently extend the operational wavelength of lasers. Downsizing of the cavity mode volume (V) and increasing the quality factor (Q) could lead to a more efficient conversion process, mediated by enhanced n-th order nonlinearities that generally scale as (Q/V)(n). Here, we demonstrate nanocavity-based SFC by utilizing photonic crystal nanocavity quantum dot lasers. The high Q and small V supported in semiconductor-based nanocavities facilitate efficient SFC to generate visible light, even with only a few photons present in the laser cavity. The combined broadband quantum dot gain and small device footprint enables the monolithic integration of 26 different-color nanolasers (spanning 493-627 nm) within a micro-scale region. These nanolasers provide a new platform for studying few-photon nonlinear optics, and for realizing full-color lasers on a single semiconductor chip. (C) 2013 Optical Society of America

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Multi-color visible light generation by self-frequency doubling in photonic crystal nanocavity quantum dot lasers

Y Ota, K Watanabe, S Iwamoto, Y Arakawa

CLEO: Science and Innovations, CTh3F. 2 (IEEE)   2013

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

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We report multi-color visible light generation from photonic crystal nanocavity lasers exhibiting broadband quantum dot gain in the near infrared. The visible emission is produced though self-frequency doubling, which efficiently occurs within the high Q nanocavities.

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Large vacuum rabi splitting in an H0 photonic crystal nanocavity-quantum dot system

D Takamiya, Y Ota, R Ohta, H Takagi, N Kumagai, S Ishida, S Iwamoto, ...

Conference on Lasers and Electro-Optics/Pacific Rim, MI2_2 (Pacific Rim Conference on Lasers and Electro-Optics, CLEO - Technical Digest)   2013

Research paper (scientific journal), Joint Work, Accepted

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We demonstrate a large vacuum Rabi splitting in an H0 photonic crystal nanocavity-quantum dot system. The nanocavity with an ultra-small mode volume enabled us to observe the largest splitting ever reported using single InAsquantum dots. © 2013 IEEE.

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Growth of high‐quality InAs quantum dots embedded in GaAs nanowire structures on Si substrates

J Kwoen, K Watanabe, Y Ota, S Iwamoto, Y Arakawa

physica status solidi (c) 10 (11), 1496-1499  2013

Research paper (scientific journal), Joint Work, Accepted

Giant optical rotation in a three-dimensional semiconductor chiral photonic crystal

S Takahashi, A Tandaechanurat, R Igusa, Y Ota, J Tatebayashi, ...

Optics express 21 (24), 29905-29913 (Optical Society of American (OSA))  21 ( 24 ) 29905 - 29913 2013

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1094-4087

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Optical rotation is experimentally demonstrated in a semiconductor-based three-dimensional chiral photonic crystal (PhC) at a telecommunication wavelength. We design a rotationally-stacked woodpile PhC structure, where neighboring layers are rotated by 45° and four layers construct a single helical unit. The mirror-asymmetric PhC made from GaAs with sub-micron periodicity is fabricated by a micro-manipulation technique. The linearly polarized light incident on the structure undergoes optical rotation during transmission. The obtained results show good agreement with numerical simulations. The measurement demonstrates the largest optical rotation angle as large as ~ 23° at 1.3 μm wavelength for a single helical unit. © 2013 Optical Society of America.

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Formation and optical properties of multi-stack InGaAs quantum dots embedded in GaAs nanowires by selective metalorganic chemical vapor deposition

J Tatebayashi, Y Ota, S Ishida, M Nishioka, S Iwamoto, Y Arakawa

Journal of crystal growth 370, 299-302  2013

Research paper (scientific journal), Joint Work, Accepted

Wide range Q-factor control in a photonic crystal nanobeam cavity incorporating quantum dots

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

CLEO: Science and Innovations, CM4F. 4 (IEEE)   2013

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

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We develop a Q-factor controllable photonic crystal nanobeam cavity incorporating quantum dots. Wide Q-factor control from 3,500 to 14,000 is demonstrated by means of MEMS, supplying bias from 0 to 18 V.

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Rabi Oscillations of a Single InAs Quantum Dot Assisted by a Photonic Crystal Nanobeam Cavity.

A Enderlin, Y Ota, S Iwamoto, Y Arakawa

JSAP Annual Meetings Extended Abstracts The 60th JSAP Spring Meeting 2013 …  2013

Joint Work

High guided mode-cavity mode coupling for an efficient extraction of spontaneous emission of a single quantum dot embedded in a photonic crystal nanobeam cavity

Alexandre Enderlin, Yasutomo Ota, Ryuichi Ohta, Naoto Kumagai, Satomi Ishida, Satoshi Iwamoto, Yasuhiko Arakawa

PHYSICAL REVIEW B (AMER PHYSICAL SOC)  86 ( 7 )  2012.08

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1098-0121

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We demonstrate efficient extraction of a single InAs quantum dot spontaneous emission through an air-suspended waveguide to which a photonic crystal nanobeam cavity is coupled. First, the quantum dot emission into the cavity mode is enhanced due to a high Purcell effect arising from a large quality factor and a small mode volume of the cavity mode. Second, the cavity photons can be efficiently transferred to the guided mode by optimizing the design of a structure that exhibits a high coupling rate between the two modes. This configuration has lead to the observation of a high extraction efficiency (79%) of the quantum dot emission through the waveguide. Moreover, as a result of the high extraction efficiency to the guided mode, the unwanted microphotoluminescence coupling to the free space modes and detected from the top surface of the sample is strongly suppressed. Indeed, we show that it exhibits a negative peak as a function of the detuning between the cavity mode energy and the quantum dot transition energy.

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Cavity quantum electrodynamics and lasing oscillation in single quantum dot-photonic crystal nanocavity coupled systems

Y Arakawa, S Iwamoto, M Nomura, A Tandaechanurat, Y Ota

IEEE Journal of Selected Topics in Quantum Electronics 18 (6), 1818-1829 (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC)  18 ( 6 ) 1818 - 1829 2012

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1077-260X

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Our recent advances in solid-state cavity quantum electrodynamics and lasing oscillation in single quantum dot (QD)-photonic crystal (PhC) nanocavity coupled systems are discussed. These include the fabrication of high-quality 2-D PhC nanocavities (Q > 50 000), which enabled the generation of spontaneous two-photon emission from a single QD, and the realization of lasing oscillation with single QD gain in the strong coupling regime. Moreover, we have fabricated high-quality 3-D PhC nanocavities (Q similar to 38 500), which have facilitated the realization of both lasing oscillation and the Purcell effect. Lasing oscillation in a 1-D PhC nanobeam cavity with gain produced by a few QDs has also been demonstrated.

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