Papers - Ota, Yasutomo

High-Q nanocavities in semiconductor-based three-dimensional photonic crystals

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

Electronics Letters 54 (5), 305-307 54 ( 5 ) 305 - 307 2018

Research paper (scientific journal), Joint Work, Accepted

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We experimentally demonstrated high quality factors (Q-factors) of
nanocavities in three-dimensional photonic crystals by increasing the in-plane
area of the structure. Entire structures made of GaAs were fabricated by a
micro-manipulation technique, and the nanocavities contained InAs
self-assembled quantum dots that emitted near-infrared light. The obtained
Q-factor was improved to 93,000, which is 2.4-times larger than that in a
previous report of a three-dimensional photonic crystal nanocavity. Due to this
large Q-factor, we successfully observed a lasing oscillation from this cavity
mode.


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Topological confinement of light in photonic crystals

S Iwamoto, Y Ota, Y Arakawa

Optics and Photonics Japan, 30aCJ1 (Optics InfoBase Conference Papers)  Part F125-OPJ 2018 2018

Research paper (scientific journal), Joint Work, Accepted

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We will discuss a topological locarized state of light realizedin a photonic crystal (PhC) nanbeam platform. By carefuly tunig the unit cell structure, we can design two topologically distinct PhC nanobeams. The bulk-edge correpondence guarantees the existence of single localized mode at the interface between them within their common bandgap. We demonstrate the lasing osscilation using the mode as a nanocavity mode.

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Time-resolved vacuum Rabi oscillations in a quantum-dot–nanocavity system

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

Physical Review B 97 (23), 235448 (AMER PHYSICAL SOC)  97 ( 23 )  2018

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2469-9950

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We report time domain observation of vacuum Rabi oscillations in a single quantum dot strongly coupled to a nanocavity under incoherent optical carrier injection. We realize a photonic crystal nanocavity with a very high quality factor of >80 000 and employ it to clearly resolve the ultrafast vacuum Rabi oscillations by simple photoluminescence-based experiments. We found that the time domain vacuum Rabi oscillations were largely modified when changing the pump wavelength and intensity, even when marginal changes were detected in the corresponding photoluminescence spectra. We analyze the measured time domain oscillations by fitting to simulation curves obtained with a cavity quantum electrodynamics model. The observed modifications of the oscillation curves were mainly induced by the change in the carrier capture and dephasing dynamics in the quantum dot, as well as the change in bare-cavity emission. This result suggests that vacuum Rabi oscillations can be utilized as a highly sensitive probe for the quantum-dot dynamics. Our work points out a powerful alternative to conventional spectral-domain measurements for a deeper understanding of the vacuum Rabi dynamics in quantum-dot-based-cavity quantum electrodynamics systems.

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Scheme for media conversion between electronic spin and photonic orbital angular momentum based on photonic nanocavity

CF Fong, Y Ota, S Iwamoto, Y Arakawa

Optics express 26 (16), 21219-21234 26 ( 16 ) 21219 - 21234 2018

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

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Light with nonzero orbital angular momentum (OAM) or twisted light is
promising for quantum communication applications such as OAM-entangled photonic
qubits. There exist photonic OAM to photonic spin angular momentum (SAM), as
well as photonic SAM to electronic SAM interfaces but not any direct photonic
OAM-electronic SAM (flying to stationary) media converter within a single
device. Here, we propose a scheme which converts photonic OAM to electronic SAM
and vice versa within a single nanophotonic device. We employed a photonic
crystal nanocavity with an embedded quantum dot (QD) which confines an electron
spin as a stationary qubit. Spin polarized emission from the QD drive the
rotation of the nanocavity modes via the strong optical spin-orbit interaction.
The rotating modes then radiate light with nonzero OAM, allowing this device to
serve as a transmitter. As this can be a unitary process, the time-reversed
case enables the device to function as a receiver. This scheme could be
generalized to other systems of resonator and quantum emitters such as a
microdisk and defects in diamond for example. Our scheme shows the potential
for realizing an (ultra)compact electronic SAM-photonic OAM interface to
accommodate OAM as an additional degree of freedom for quantum information
purposes.


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Quantum-dot nanolasers on Si photonic circuits

A Osada, Y Ota, R Katsumi, K Watanabe, S Iwamoto, Y Arakawa

2018 Conference on Lasers and Electro-Optics (CLEO), 1-2 (2018 Conference on Lasers and Electro-Optics, CLEO 2018 - Proceedings)  Part F94-CLEO\_SI 2018 2018

Research paper (scientific journal), Joint Work, Accepted

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We report the hybrid integration of quantum dot nanolasers on silicon photonic circuits using transfer printing. The pick-and-place assembly method facilitates the integration of two nanolasers on a single CMOS-processed waveguide that supports two-wavelength output.

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Quantum dot single photon sources transfer-printed on wire waveguides

R Katsumi, Y Ota, M Kakuda, S Iwamoto, Y Arakawa

CLEO: QELS_Fundamental Science, FM1H. 5 (OSA - The Optical Society)  2018 2018

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

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We report quantum dot single photon sources coupled to glass-clad wire waveguides by transfer printing, which enables the heterogeneous source integration in a simple pick-and-place manner. A high waveguide coupling efficiency &gt
60% is experimentally demonstrated.

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Nanowire–quantum-dot lasers on flexible membranes

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

Applied Physics Express 11 (6), 065002  2018

Research paper (scientific journal), Joint Work, Accepted

Lasing in a topological photonic crystal nanocavity

Y Ota, R Katsumi, K Watanabe, S Iwamoto, Y Arakawa

CLEO: Science and Innovations, STh3A. 4 (OSA - The Optical Society)  2018 2018

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

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We report lasing oscillation in a zero-dimensional edge state formed at the boundary of two photonic crystal nanobeams with distinct band topologies. The topological origin of the nanocavity mode ensures a single mode operation.

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Large vacuum Rabi splitting between a single quantum dot and an H0 photonic crystal nanocavity

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

Applied Physics Letters 112 (9), 093101 (American Institute of Physics Inc.)  112 ( 9 )  2018

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

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Strong light matter interactions between semiconductor quantum dots and optical micro/nanocavities are useful resources for developing quantum information processing devices and for exploring diverse quantum optical phenomena. In pursuit of better device performances and novel physics, it is desirable to achieve a larger coupling constant between the quantum dot and the cavity while keeping the high coherence of the coupled system. In this letter, we report the observation of a large vacuum Rabi splitting of ∼328 μeV using a single InAs quantum dot embedded in a GaAs-based H0 photonic crystal nanocavity, which possesses a near-diffraction limited mode volume as well as a high experimental Q factor of ∼52 000. The resulting figure of merit of the strongly coupled systems, defined as a ratio of the coupling constant to the cavity decay rate, reaches 6.4, which is the record high value for semiconductor QD-nanocavity systems reported to date.

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Topological photonic crystal nanocavity laser

Y Ota, R Katsumi, K Watanabe, S Iwamoto, Y Arakawa

Communications Physics 1 (1), 1-8 (Springer Science and Business Media LLC)  1 ( 1 )  2018

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2399-3650

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Topological edge states exist at the interfaces between two
topologically-distinct materials. The presence and number of such modes are
deterministically predicted from the bulk-band topologies, known as the
bulk-edge correspondence. This principle is highly useful for predictably
controlling optical modes in resonators made of photonic crystals (PhCs),
leading to the recent demonstrations of micro-scale topological lasers.
Meanwhile, zero-dimensional topological trapped states in the nanoscale
remained unexplored, despite its importance for enhancing light-matter
interactions and for wide applications including single-mode nanolasers. Here,
we report a topological PhC nanocavity with a near-diffraction-limited mode
volume and its application to single-mode lasing. The topological origin of the
nanocavity, formed at the interface between two topologically-distinct PhCs,
guarantees the existence of only one mode within its photonic bandgap. The
observed lasing accompanies a high spontaneous emission coupling factor
stemming from the nanoscale confinement. These results encompass a way to
greatly downscale topological photonics.


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world's highest Q‐Factor: Fabrication of a large‐area 3D photonic crystal for 3D photonic circuits

anonymous

Electronics Letters 54 (5), 257-257  2018

Research paper (scientific journal), Joint Work, Accepted

Two dimensional photonic crystal nanocavities with InAs/GaAs quantum dot active regions embedded by MBE regrowth

QH Vo, Y Ota, K Watanabe, T Kageyama, S Iwamoto, Y Arakawa

Japanese Journal of Applied Physics 57 (8S2), 08PD03 57 ( 8 )  2018

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

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Transfer-printed single-photon sources coupled to wire waveguides

R Katsumi, Y Ota, M Kakuda, S Iwamoto, Y Arakawa

Optica 5 (6), 691-694 (The Optical Society)  5 ( 6 ) 691 - 691 2018

Research paper (scientific journal), Joint Work, Accepted,  ISSN  2334-2536

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Photonic integrated circuits (PICs) are attractive platforms to perform
large-scale quantum information processing. While highly-functional PICs (e.g.
silicon based photonic-circuits) and high-performance single photon sources
(SPSs, e.g. compound-semiconductor quantum dots (QDs)) have been independently
demonstrated, their combination for single-photon-based applications has still
been limited. This is largely due to the complexities of introducing SPSs into
existing PIC platforms, which are generally realized with different materials
and using distinct fabrication protocols. Here, we report a novel approach to
combine SPSs and PICs prepared independently. We employ transfer printing, by
which multiple desired SPSs can be integrated in a simple pick-and-place manner
with a theoretical waveguide coupling efficiency >99%, fulfilling the demanding
requirements of large-scale quantum applications. Experimentally, we
demonstrated QD-based SPSs with high waveguide coupling efficiencies, together
with the integration of two SPSs into a waveguide. Our approach will accelerate
scalable fusion between modern PICs and cutting-edge quantum technologies.


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Transfer-printed quantum-dot nanolasers on a silicon photonic circuit

A Osada, Y Ota, R Katsumi, K Watanabe, S Iwamoto, Y Arakawa

Applied Physics Express 11 (7), 072002 (Japan Society of Applied Physics)  11 ( 7 )  2018

Research paper (scientific journal), Joint Work, Accepted,  ISSN  1882-0786

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Quantum-dot (QD) nanolasers integrated on a silicon photonic circuit are demonstrated for the first time. QD nanolasers based on one-dimensional photonic crystal nanocavities containing InAs/GaAs QDs are integrated on CMOS-processed silicon waveguides with silicon dioxide cladding. We employed transfer printing, whereby the three-dimensional stack of photonic nanostructures is assembled in a pick-and-place manner. The lasing operation and waveguide coupling of an assembled single nanolaser are confirmed through micro-photoluminescence spectroscopy. Furthermore, by repetitive transfer printing, two QD nanolasers integrated onto a single silicon waveguide are demonstrated, opening a path to the development of compact light sources potentially applicable to wavelength division multiplexing.

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IEICE Technical Report

ST KIT, Y Ota, T Tajiri, J Tatebayashi, S Iwamoto, Y Arakawa, ...

Workshop Date 118 (128)  2018

Joint Work

Control of angular momentum of photons by photonic nanostructures

S Iwamoto, Y Ota, CF Fong, Y Arakawa

JSAP Annual Meetings Extended Abstracts The 65th JSAP Spring Meeting 2018, 47-47  2018

Joint Work

Single photon emission and lasing oscillation in a plasmonic microring resonator containing self-assembled quantum dots

A Tamada, Y Ota, K Kuruma, K Watanabe, S Iwamoto, Y Arakawa

IEICE Technical Report; IEICE Tech. Rep. 117 (407), 269-274  2018

Joint Work

Scheme for Optical Orbital-to-Electronic Spin Angular Momentum Media Conversion using a Photonic Crystal Nanocavity

CF Fong, Y Ota, S Iwamoto, Y Arakawa

JSAP Annual Meetings Extended Abstracts The 65th JSAP Spring Meeting 2018 …  2018

Joint Work

High‐Q nanocavities in semiconductor‐based three‐dimensional photonic crystals

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

Electronics Letters 54 (5), 305-307  2018

Joint Work

Control of circularly polarized light emission by semiconductor-based three-dimensional chiral photonic crystals

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

IEICE Technical Report; IEICE Tech. Rep. 117 (407), 1-4  2018

Joint Work