1
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Fricker D, Atkinson P, Jin X, Lepsa M, Zeng Z, Kovács A, Kibkalo L, Dunin-Borkowski RE, Kardynał BE. Effect of surface gallium termination on the formation and emission energy of an InGaAs wetting layer during the growth of InGaAs quantum dots by droplet epitaxy. NANOTECHNOLOGY 2023; 34:145601. [PMID: 36595322 DOI: 10.1088/1361-6528/acabd1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/14/2022] [Indexed: 06/17/2023]
Abstract
Self-assembled quantum dots (QDs) based on III-V semiconductors have excellent properties for applications in quantum optics. However, the presence of a 2D wetting layer (WL) which forms during the Stranski-Krastanov growth of QDs can limit their performance. Here, we investigate WL formation during QD growth by the droplet epitaxy technique. We use a combination of photoluminescence excitation spectroscopy, lifetime measurements, and transmission electron microscopy to identify the presence of an InGaAs WL in these droplet epitaxy QDs, even in the absence of distinguishable WL luminescence. We observe that increasing the amount of Ga deposited on a GaAs (100) surface prior to the growth of InGaAs QDs leads to a significant reduction in the emission wavelength of the WL to the point where it can no longer be distinguished from the GaAs acceptor peak emission in photoluminescence measurements. However increasing the amount of Ga deposited does not suppress the formation of a WL under the growth conditions used here.
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Affiliation(s)
- D Fricker
- Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany
| | - P Atkinson
- Institut des Nano Sciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - X Jin
- Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany
| | - M Lepsa
- Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany
- Peter Grünberg Institute 10, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Z Zeng
- Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany
| | - A Kovács
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute 5, Forschungszentrum Jülich, D-52428 Jülich, Germany
| | - L Kibkalo
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute 5, Forschungszentrum Jülich, D-52428 Jülich, Germany
| | - R E Dunin-Borkowski
- Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute 5, Forschungszentrum Jülich, D-52428 Jülich, Germany
| | - B E Kardynał
- Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany
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2
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Denning EV, Knorr A, Katsch F, Richter M. Efficient Quadrature Squeezing from Biexcitonic Parametric Gain in Atomically Thin Semiconductors. PHYSICAL REVIEW LETTERS 2022; 129:097401. [PMID: 36083637 DOI: 10.1103/physrevlett.129.097401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/17/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Modification of electromagnetic quantum fluctuations in the form of quadrature squeezing is a central quantum resource, which can be generated from nonlinear optical processes. Such a process is facilitated by coherent two-photon excitation of the strongly bound biexciton in atomically thin semiconductors. We show theoretically that interfacing an atomically thin semiconductor with an optical cavity makes it possible to harness this two-photon resonance and use the biexcitonic parametric gain to generate squeezed light with input power an order of magnitude below current state-of-the-art devices with conventional third-order nonlinear materials that rely on far off-resonant nonlinearities. Furthermore, the squeezing bandwidth is found to be in the range of several meV. These results identify atomically thin semiconductors as a promising candidate for on-chip squeezed-light sources.
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Affiliation(s)
- Emil V Denning
- Nichtlineare Optik und Quantenelektronik, Institut für Theoretische Physik, Technische Universität Berlin, 10623 Berlin, Germany
| | - Andreas Knorr
- Nichtlineare Optik und Quantenelektronik, Institut für Theoretische Physik, Technische Universität Berlin, 10623 Berlin, Germany
| | - Florian Katsch
- Nichtlineare Optik und Quantenelektronik, Institut für Theoretische Physik, Technische Universität Berlin, 10623 Berlin, Germany
| | - Marten Richter
- Nichtlineare Optik und Quantenelektronik, Institut für Theoretische Physik, Technische Universität Berlin, 10623 Berlin, Germany
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3
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Bleyan YY, Mantashyan PA, Kazaryan EM, Sarkisyan HA, Accorsi G, Baskoutas S, Hayrapetyan DB. Non-Linear Optical Properties of Biexciton in Ellipsoidal Quantum Dot. NANOMATERIALS 2022; 12:nano12091412. [PMID: 35564121 PMCID: PMC9101687 DOI: 10.3390/nano12091412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/11/2022] [Accepted: 04/13/2022] [Indexed: 02/06/2023]
Abstract
We have presented a theoretical investigation of exciton and biexciton states for the ground and excited levels in a strongly oblate ellipsoidal quantum dot made from GaAs. The variational trial wave functions for the ground and excited states of the exciton and biexciton are constructed on the base of one-particle wave functions. The energies for the ground and excited levels, depending on the ellipsoidal quantum dot’s geometrical parameters, are depicted in the framework of the variational method. The oscillator strength of the transition from exciton to biexciton states for ground and excited levels is investigated as a function of the ellipsoidal quantum dot’s small and large semiaxes. The third-order optical susceptibilities of ground and excited biexcitons around one-photon and two-photon resonances are calculated as a function of the photon energy. The dependences of third-order optical susceptibilities for the ground and excited levels on the photon energy for different values of the ellipsoidal quantum dot’s semiaxis are revealed. The absorption coefficients in the ellipsoidal quantum dot, both for ground and excited states of exciton and biexciton, are calculated. The absorption coefficients for the ground level of exciton and biexciton for the fixed value of the large semiaxis and for the different values of the small semiaxis are determined. Finally, the two-photon absorption coefficient of the biexciton in the GaAs ellipsoidal quantum dot is computed.
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Affiliation(s)
- Yuri Y. Bleyan
- Department of General Physics and Quantum Nanostructures, Russian-Armenian University, Yerevan 0051, Armenia; (Y.Y.B.); (P.A.M.); (E.M.K.); (H.A.S.)
| | - Paytsar A. Mantashyan
- Department of General Physics and Quantum Nanostructures, Russian-Armenian University, Yerevan 0051, Armenia; (Y.Y.B.); (P.A.M.); (E.M.K.); (H.A.S.)
- Photonics Laboratory, Institute for Physical Research of NAS RA, Ashtarak 0203, Armenia
| | - Eduard M. Kazaryan
- Department of General Physics and Quantum Nanostructures, Russian-Armenian University, Yerevan 0051, Armenia; (Y.Y.B.); (P.A.M.); (E.M.K.); (H.A.S.)
- Institute of Electronics and Telecommunications, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
| | - Hayk A. Sarkisyan
- Department of General Physics and Quantum Nanostructures, Russian-Armenian University, Yerevan 0051, Armenia; (Y.Y.B.); (P.A.M.); (E.M.K.); (H.A.S.)
- Institute of Electronics and Telecommunications, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
| | - Gianluca Accorsi
- CNR NANOTEC, Institute of Nanotechnology, University Campus Ecotekne, 73100 Lecce, Italy;
| | - Sotirios Baskoutas
- Department of Materials Science, University of Patras, 265 04 Patras, Greece;
| | - David B. Hayrapetyan
- Department of General Physics and Quantum Nanostructures, Russian-Armenian University, Yerevan 0051, Armenia; (Y.Y.B.); (P.A.M.); (E.M.K.); (H.A.S.)
- Institute of Electronics and Telecommunications, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
- Correspondence: ; Tel.: +374-9393-4311
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4
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Abstract
Tailored nanoscale quantum light sources, matching the specific needs of use cases, are crucial building blocks for photonic quantum technologies. Several different approaches to realize solid-state quantum emitters with high performance have been pursued and different concepts for energy tuning have been established. However, the properties of the emitted photons are always defined by the individual quantum emitter and can therefore not be controlled with full flexibility. Here we introduce an all-optical nonlinear method to tailor and control the single photon emission. We demonstrate a laser-controlled down-conversion process from an excited state of a semiconductor quantum three-level system. Based on this concept, we realize energy tuning and polarization control of the single photon emission with a control-laser field. Our results mark an important step towards tailored single photon emission from a photonic quantum system based on quantum optical principles.
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5
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Sbresny F, Hanschke L, Schöll E, Rauhaus W, Scaparra B, Boos K, Zubizarreta Casalengua E, Riedl H, Del Valle E, Finley JJ, Jöns KD, Müller K. Stimulated Generation of Indistinguishable Single Photons from a Quantum Ladder System. PHYSICAL REVIEW LETTERS 2022; 128:093603. [PMID: 35302816 DOI: 10.1103/physrevlett.128.093603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
We propose a scheme for the generation of highly indistinguishable single photons using semiconductor quantum dots and demonstrate its performance and potential. The scheme is based on the resonant two-photon excitation of the biexciton followed by stimulation of the biexciton to selectively prepare an exciton. Quantum-optical simulations and experiments are in good agreement and show that the scheme provides significant advantages over previously demonstrated excitation methods. The two-photon excitation of the biexciton suppresses re-excitation and enables ultralow multiphoton errors, while the precisely timed stimulation pulse results in very low timing jitter of the photons, and consequently, high indistinguishability. In addition, the polarization of the stimulation pulse allows us to deterministically program the polarization of the emitted photon (H or V). This ensures that all emission of interest occurs in the polarization of the detection channel, resulting in higher brightness than cross-polarized resonant excitation.
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Affiliation(s)
- Friedrich Sbresny
- Walter Schottky Institut, Department of Electrical and Computer Engineering and MCQST, Technische Universität München, 85748 Garching, Germany
| | - Lukas Hanschke
- Walter Schottky Institut, Department of Electrical and Computer Engineering and MCQST, Technische Universität München, 85748 Garching, Germany
| | - Eva Schöll
- Institute for Photonic Quantum Systems (PhoQS), Center for Optoelectronics and Photonics Paderborn (CeOPP) and Department of Physics, Paderborn University, 33098 Paderborn, Germany
| | - William Rauhaus
- Walter Schottky Institut, Department of Electrical and Computer Engineering and MCQST, Technische Universität München, 85748 Garching, Germany
| | - Bianca Scaparra
- Walter Schottky Institut, Department of Electrical and Computer Engineering and MCQST, Technische Universität München, 85748 Garching, Germany
| | - Katarina Boos
- Walter Schottky Institut, Department of Electrical and Computer Engineering and MCQST, Technische Universität München, 85748 Garching, Germany
| | - Eduardo Zubizarreta Casalengua
- Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton WV1 1LY, United Kingdom
- Departamento de Física Teórica de la Materia Condensada and IFIMAC, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Hubert Riedl
- Walter Schottky Institut, Department of Physics and MCQST, Technische Universität München, 85748 Garching, Germany
| | - Elena Del Valle
- Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton WV1 1LY, United Kingdom
- Departamento de Física Teórica de la Materia Condensada and IFIMAC, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Institute for Advanced Study, Technische Universität München, 85748 Garching, Germany
| | - Jonathan J Finley
- Walter Schottky Institut, Department of Physics and MCQST, Technische Universität München, 85748 Garching, Germany
| | - Klaus D Jöns
- Institute for Photonic Quantum Systems (PhoQS), Center for Optoelectronics and Photonics Paderborn (CeOPP) and Department of Physics, Paderborn University, 33098 Paderborn, Germany
| | - Kai Müller
- Walter Schottky Institut, Department of Electrical and Computer Engineering and MCQST, Technische Universität München, 85748 Garching, Germany
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6
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Safwan SA, El Meshad N. Stability of Excited Exciton States in Semiconductor Quantum Dots Under a Lateral Electric Field. INTERNATIONAL JOURNAL OF NANOSCIENCE 2021. [DOI: 10.1142/s0219581x21500393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The effect of the lateral electric field (LEF) on the excited and ground state stability of an exciton ([Formula: see text]) confined in a parabolic cylindrical quantum dot (QD) was estimated in this study. The calculation was performed in the framework of single-band effective mass theory using a variational approach. Our results revealed that the ground state binding energy of [Formula: see text] decreases with increasing the cylindrical QD radius until the exciton stability is lost at moderate LEF strength. By increasing the LEF strength, the excited heavy-hole ([Formula: see text]) can create an excited state [Formula: see text] or excited state [Formula: see text] of [Formula: see text], and the results indicate that the first state is more stable. In contrast, when an excited electron ([Formula: see text]) combines with an excited hole ([Formula: see text]) or unexcited hole ([Formula: see text]), it contains no split excited states for [Formula: see text] with less binding energy than the state [Formula: see text]. Comparing our previous results of donor impurity [Formula: see text] with [Formula: see text], we found that [Formula: see text] has a more stable ground state than [Formula: see text]. Moreover, the excited [Formula: see text] states are more stable than the excited states of [Formula: see text]. The quantum Stark shift (QSS) of the light- and heavy-hole exciton energy was explored, and a blue-shifted and quadratic QSS was observed. In contrast, for single particles (electron, heavy-hole and light hole), a red-shifted and linear QSS was observed.
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Affiliation(s)
- S. A. Safwan
- Theoretical Physics Department, National Research Centre, Dokki, Cairo, Egypt
| | - Nagwa El Meshad
- Theoretical Physics Department, National Research Centre, Dokki, Cairo, Egypt
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7
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Goktas NI, Dubrovskii VG, LaPierre RR. Conformal Growth of Radial InGaAs Quantum Wells in GaAs Nanowires. J Phys Chem Lett 2021; 12:1275-1283. [PMID: 33497239 DOI: 10.1021/acs.jpclett.0c03712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
GaAs-InGaAs-GaAs core-shell-shell nanowire (NW) structures were grown by gas source molecular beam epitaxy using the selective-area, self-assisted, vapor-liquid-solid method. The structural, morphological, and optical properties of the NWs were examined for different growth conditions of the InGaAs shell. With increasing In concentration of the InGaAs shell, the growth transitioned from preferential deposition at the NW base to the Stranski-Krastanov growth mode where InGaAs islands formed along the NW length. This trend is explained within a nucleation model where there is a critical In flux below which the conformal growth is suppressed and the shell forms only at the NW base. Low growth temperature produced a more uniform In distribution along the NW length but resulted in quenching of the photoluminescence (PL) emission. Alternatively, reducing the shell thickness and increasing the V/III flux ratio resulted in conformal InGaAs shell growth and quantum dot-like PL emission. Our results indicate a pathway toward the conditions for conformal InGaAs shell growth required for satisfactory optoelectronic performance.
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Affiliation(s)
- Nebile Isik Goktas
- Department of Engineering Physics, McMaster University, Hamilton, ON L8S 4L7, Canada
| | - Vladimir G Dubrovskii
- Department of Physics, St. Petersburg State University, Universitetskaya Emb. 13B, 199034 St. Petersburg, Russia
| | - Ray R LaPierre
- Department of Engineering Physics, McMaster University, Hamilton, ON L8S 4L7, Canada
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8
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Yeo HS, Lee K, Cho JH, Park SH, Cho YH. Control of the 3-Fold Symmetric Shape of Group III-Nitride Quantum Dots: Suppression of Fine-Structure Splitting. NANO LETTERS 2020; 20:8461-8468. [PMID: 32910661 DOI: 10.1021/acs.nanolett.0c02236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Controlling the in-plane symmetry of wide-bandgap semiconductor quantum dots (QDs) is essential for room temperature quantum photonic applications using polarization entangled photon pairs. Herein, we report the formation of 3-fold symmetric group III-nitride QDs at the apex of a triangular pyramid via a self-limited growth mechanism. We employed the in-plane rotational symmetry of the c-plane of a Wurtzite crystal and the large built-in piezoelectric field to reduce fine-structure splitting. The QDs exhibit emission that is distinguishable from that of sidewall quantum wells, and the biexciton-exciton cascade possesses a single-photon nature. We observed the relatively low optical polarization anisotropy and small fine structure splitting under the measurement limit (270 μeV) with the 3-fold symmetric QD. In contrast with current strategies that consider group III-nitride QDs as strongly polarized single-photon emitters, our approach for controlling the QD symmetry provides a new perspective on such QDs, as polarization-entangled photon pairs.
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Affiliation(s)
- Hwan-Seop Yeo
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Kwanjae Lee
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Jong-Hoi Cho
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Seoung-Hwan Park
- Department of Electronics Engineering, Catholic University of Daegu, Kyeongsan 38430, Republic of Korea
| | - Yong-Hoon Cho
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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9
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Srimath Kandada AR, Li H, Thouin F, Bittner ER, Silva C. Stochastic scattering theory for excitation-induced dephasing: Time-dependent nonlinear coherent exciton lineshapes. J Chem Phys 2020; 153:164706. [PMID: 33138398 DOI: 10.1063/5.0026351] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
We develop a stochastic theory that treats time-dependent exciton-exciton s-wave scattering and that accounts for dynamic Coulomb screening, which we describe within a mean-field limit. With this theory, we model excitation-induced dephasing effects on time-resolved two-dimensional coherent optical lineshapes and we identify a number of features that can be attributed to the many-body dynamics occurring in the background of the exciton, including dynamic line narrowing, mixing of real and imaginary spectral components, and multi-quantum states. We test the model by means of multidimensional coherent spectroscopy on a two-dimensional metal-halide semiconductor that hosts tightly bound excitons and biexcitons that feature strong polaronic character. We find that the exciton nonlinear coherent lineshape reflects many-body correlations that give rise to excitation-induced dephasing. Furthermore, we observe that the exciton lineshape evolves with the population time over time windows in which the population itself is static in a manner that reveals the evolution of the multi-exciton many-body couplings. Specifically, the dephasing dynamics slow down with time, at a rate that is governed by the strength of exciton many-body interactions and on the dynamic Coulomb screening potential. The real part of the coherent optical lineshape displays strong dispersive character at zero time, which transforms to an absorptive lineshape on the dissipation timescale of excitation-induced dephasing effects, while the imaginary part displays converse behavior. Our microscopic theoretical approach is sufficiently flexible to allow for a wide exploration of how system-bath dynamics contribute to linear and non-linear time-resolved spectral behavior.
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Affiliation(s)
- Ajay Ram Srimath Kandada
- Department of Physics and Center for Functional Materials, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, North Carolina 27109, USA
| | - Hao Li
- Department of Chemistry, University of Houston, Houston, Texas 77204, USA
| | - Félix Thouin
- School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332, USA
| | - Eric R Bittner
- Department of Chemistry, University of Houston, Houston, Texas 77204, USA
| | - Carlos Silva
- School of Physics, Georgia Institute of Technology, 837 State Street, Atlanta, Georgia 30332, USA
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10
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Schuck CF, Roy SK, Garrett T, Yuan Q, Wang Y, Cabrera CI, Grossklaus KA, Vandervelde TE, Liang B, Simmonds PJ. Anomalous Stranski-Krastanov growth of (111)-oriented quantum dots with tunable wetting layer thickness. Sci Rep 2019; 9:18179. [PMID: 31796804 PMCID: PMC6890744 DOI: 10.1038/s41598-019-54668-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 11/19/2019] [Indexed: 11/09/2022] Open
Abstract
Driven by tensile strain, GaAs quantum dots (QDs) self-assemble on In0.52Al0.48As(111)A surfaces lattice-matched to InP substrates. In this study, we show that the tensile-strained self-assembly process for these GaAs(111)A QDs unexpectedly deviates from the well-known Stranski-Krastanov (SK) growth mode. Traditionally, QDs formed via the SK growth mode form on top of a flat wetting layer (WL) whose thickness is fixed. The inability to tune WL thickness has inhibited researchers' attempts to fully control QD-WL interactions in these hybrid 0D-2D quantum systems. In contrast, using microscopy, spectroscopy, and computational modeling, we demonstrate that for GaAs(111)A QDs, we can continually increase WL thickness with increasing GaAs deposition, even after the tensile-strained QDs (TSQDs) have begun to form. This anomalous SK behavior enables simultaneous tuning of both TSQD size and WL thickness. No such departure from the canonical SK growth regime has been reported previously. As such, we can now modify QD-WL interactions, with future benefits that include more precise control of TSQD band structure for infrared optoelectronics and quantum optics applications.
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Affiliation(s)
- Christopher F Schuck
- Micron School of Materials Science & Engineering, Boise State University, Boise, Idaho, 83725, USA
- Materials Growth Facility, University of Delaware, Newark, Delaware, 19716, USA
| | - Simon K Roy
- Department of Physics, Boise State University, Boise, Idaho, 83725, USA
| | - Trent Garrett
- Department of Physics, Boise State University, Boise, Idaho, 83725, USA
| | - Qing Yuan
- College of Physics Science & Technology, Hebei University, Baoding, 071002, P.R. China
| | - Ying Wang
- College of Physics Science & Technology, Hebei University, Baoding, 071002, P.R. China
| | - Carlos I Cabrera
- Center for Research in Sciences, Research Institute in Basic and Applied Sciences, Autonomous University of the State of Morelos, Av. Universidad 1001, 62209, Cuernavaca, Morelos, Mexico
| | - Kevin A Grossklaus
- Department of Electrical and Computer Engineering, Tufts University, 161 College Avenue, Medford, Massachusetts, 02155, USA
| | - Thomas E Vandervelde
- Department of Electrical and Computer Engineering, Tufts University, 161 College Avenue, Medford, Massachusetts, 02155, USA
| | - Baolai Liang
- College of Physics Science & Technology, Hebei University, Baoding, 071002, P.R. China
| | - Paul J Simmonds
- Micron School of Materials Science & Engineering, Boise State University, Boise, Idaho, 83725, USA.
- Department of Physics, Boise State University, Boise, Idaho, 83725, USA.
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11
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Highly-efficient extraction of entangled photons from quantum dots using a broadband optical antenna. Nat Commun 2018; 9:2994. [PMID: 30065263 PMCID: PMC6068148 DOI: 10.1038/s41467-018-05456-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 07/01/2018] [Indexed: 12/02/2022] Open
Abstract
Many quantum photonic technologies require the efficient generation of entangled pairs of photons, but to date there have been few ways to produce them reliably. Sources based on parametric down conversion operate at very low efficiency per pulse due to the probabilistic generation process. Semiconductor quantum dots can emit single pairs of entangled photons deterministically but they fall short due to the extremely low-extraction efficiency. Strategies for extracting single photons from quantum dots, such as embedding them in narrowband optical cavities, are difficult to translate to entangled photons. Here, we build a broadband optical antenna with an extraction efficiency of 65% ± 4% and demonstrate a highly-efficient entangled-photon source by collecting strongly entangled photons (fidelity of 0.9) at a pair efficiency of 0.372 ± 0.002 per pulse. The high brightness achieved by our source represents a step forward in the development of optical quantum technologies. Cascade radiative decay in quantum dots is a promising way of generating entangled photon pairs, but the extraction efficiency is a strongly limiting factor. Here, the authors demonstrate high extraction efficiency through a broadband dielectric photonic antenna.
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12
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Qian C, Wu S, Song F, Peng K, Xie X, Yang J, Xiao S, Steer MJ, Thayne IG, Tang C, Zuo Z, Jin K, Gu C, Xu X. Two-Photon Rabi Splitting in a Coupled System of a Nanocavity and Exciton Complexes. PHYSICAL REVIEW LETTERS 2018; 120:213901. [PMID: 29883144 DOI: 10.1103/physrevlett.120.213901] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Indexed: 05/27/2023]
Abstract
Two-photon Rabi splitting in a cavity-dot system provides a basis for multiqubit coherent control in a quantum photonic network. Here we report on two-photon Rabi splitting in a strongly coupled cavity-dot system. The quantum dot was grown intentionally large in size for a large oscillation strength and small biexciton binding energy. Both exciton and biexciton transitions couple to a high-quality-factor photonic crystal cavity with large coupling strengths over 130 μeV. Furthermore, the small binding energy enables the cavity to simultaneously couple with two exciton states. Thereby, two-photon Rabi splitting between the biexciton and cavity is achieved, which can be well reproduced by theoretical calculations with quantum master equations.
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Affiliation(s)
- Chenjiang Qian
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shiyao Wu
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Feilong Song
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kai Peng
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Xie
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingnan Yang
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shan Xiao
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Matthew J Steer
- School of Engineering, University of Glasgow, Glasgow G12 8LT, United Kingdom
| | - Iain G Thayne
- School of Engineering, University of Glasgow, Glasgow G12 8LT, United Kingdom
| | - Chengchun Tang
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
| | - Zhanchun Zuo
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
| | - Kuijuan Jin
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changzhi Gu
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiulai Xu
- Institute of Physics, Chinese Academy of Science, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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13
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Luo XQ, Li ZZ, Jing J, Xiong W, Li TF, Yu T. Spectral features of the tunneling-induced transparency and the Autler-Townes doublet and triplet in a triple quantum dot. Sci Rep 2018; 8:3107. [PMID: 29449588 PMCID: PMC5814457 DOI: 10.1038/s41598-018-21221-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/31/2018] [Indexed: 12/03/2022] Open
Abstract
We theoretically investigate the spectral features of tunneling-induced transparency (TIT) and Autler-Townes (AT) doublet and triplet in a triple-quantum-dot system. By analyzing the eigenenergy spectrum of the system Hamiltonian, we can discriminate TIT and double TIT from AT doublet and triplet, respectively. For the resonant case, the presence of the TIT does not exhibit distinguishable anticrossing in the eigenenergy spectrum in the weak-tunneling regime, while the occurrence of double anticrossings in the strong-tunneling regime shows that the TIT evolves to the AT doublet. For the off-resonance case, the appearance of a new detuning-dependent dip in the absorption spectrum leads to double TIT behavior in the weak-tunneling regime due to no distinguished anticrossing occurring in the eigenenergy spectrum. However, in the strong-tunneling regime, a new detuning-dependent dip in the absorption spectrum results in AT triplet owing to the presence of triple anticrossings in the eigenenergy spectrum. Our results can be applied to quantum measurement and quantum-optics devices in solid systems.
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Affiliation(s)
- Xiao-Qing Luo
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Zeng-Zhao Li
- Beijing Computational Science Research Center, Beijing, 100193, China.
| | - Jun Jing
- Department of Physics, Zhejiang University, Hangzhou, 310027, Zhejiang, China
| | - Wei Xiong
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Tie-Fu Li
- Beijing Computational Science Research Center, Beijing, 100193, China. .,Institute of Microelectronics, Department of Microelectronics and Nanoelectronics and Tsinghua National Laboratory of Information Science and Technology, Tsinghua University, Beijing, 100084, China.
| | - Ting Yu
- Beijing Computational Science Research Center, Beijing, 100193, China.,Department of Physics and Engineering Physics, Center for Controlled Quantum Systems, Stevens Institute of Technology, Hoboken, New Jersey, 07030, USA
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14
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da Silva SFC, Mardegan T, de Araújo SR, Ramirez CAO, Kiravittaya S, Couto ODD, Iikawa F, Deneke C. Fabrication and Optical Properties of Strain-free Self-assembled Mesoscopic GaAs Structures. NANOSCALE RESEARCH LETTERS 2017; 12:61. [PMID: 28110446 PMCID: PMC5253139 DOI: 10.1186/s11671-016-1782-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 12/09/2016] [Indexed: 06/06/2023]
Abstract
We use a combined process of Ga-assisted deoxidation and local droplet etching to fabricate unstrained mesoscopic GaAs/AlGaAs structures exhibiting a high shape anisotropy with a length up to 1.2 μm and a width of 150 nm. We demonstrate good controllability over size and morphology of the mesoscopic structures by tuning the growth parameters. Our growth method yields structures, which are coupled to a surrounding quantum well and present unique optical emission features. Microscopic and optical analysis of single structures allows us to demonstrate that single structure emission originates from two different confinement regions, which are spectrally separated and show sharp excitonic lines. Photoluminescence is detected up to room temperature making the structures the ideal candidates for strain-free light emitting/detecting devices.
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Affiliation(s)
- Saimon Filipe Covre da Silva
- Laboratório Nacional de Nanotecnologia (LNNano/CNPEM), 13083-100 Campinas, SP Brazil
- Departamento de Física, Universidade Federal de Viçosa, 36570-900 Viçosa, MG Brazil
| | - Thayná Mardegan
- Laboratório Nacional de Nanotecnologia (LNNano/CNPEM), 13083-100 Campinas, SP Brazil
- Universidade Federal de Itajubá, Campus Itabira, 35903-087 Itabira, MG Brazil
| | | | | | - Suwit Kiravittaya
- Department of Electrical and Computer Engineering, Faculty of Engineering, Naresuan University, Phitsanulok, 65000 Thailand
| | - Odilon D. D. Couto
- Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, 13083-859 Campinas, SP Brazil
| | - Fernando Iikawa
- Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas, 13083-859 Campinas, SP Brazil
| | - Christoph Deneke
- Laboratório Nacional de Nanotecnologia (LNNano/CNPEM), 13083-100 Campinas, SP Brazil
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15
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Reindl M, Jöns KD, Huber D, Schimpf C, Huo Y, Zwiller V, Rastelli A, Trotta R. Phonon-Assisted Two-Photon Interference from Remote Quantum Emitters. NANO LETTERS 2017; 17:4090-4095. [PMID: 28557459 PMCID: PMC5512156 DOI: 10.1021/acs.nanolett.7b00777] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 05/17/2017] [Indexed: 05/26/2023]
Abstract
Photonic quantum technologies are on the verge of finding applications in everyday life with quantum cryptography and quantum simulators on the horizon. Extensive research has been carried out to identify suitable quantum emitters and single epitaxial quantum dots have emerged as near-optimal sources of bright, on-demand, highly indistinguishable single photons and entangled photon-pairs. In order to build up quantum networks, it is essential to interface remote quantum emitters. However, this is still an outstanding challenge, as the quantum states of dissimilar "artificial atoms" have to be prepared on-demand with high fidelity and the generated photons have to be made indistinguishable in all possible degrees of freedom. Here, we overcome this major obstacle and show an unprecedented two-photon interference (visibility of 51 ± 5%) from remote strain-tunable GaAs quantum dots emitting on-demand photon-pairs. We achieve this result by exploiting for the first time the full potential of a novel phonon-assisted two-photon excitation scheme, which allows for the generation of highly indistinguishable (visibility of 71 ± 9%) entangled photon-pairs (fidelity of 90 ± 2%), enables push-button biexciton state preparation (fidelity of 80 ± 2%) and outperforms conventional resonant two-photon excitation schemes in terms of robustness against environmental decoherence. Our results mark an important milestone for the practical realization of quantum repeaters and complex multiphoton entanglement experiments involving dissimilar artificial atoms.
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Affiliation(s)
- Marcus Reindl
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University, Linz 4040, Austria
| | - Klaus D. Jöns
- Department
of Applied Physics, Royal Institute of Technology, Stockholm 106 91, Sweden
| | - Daniel Huber
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University, Linz 4040, Austria
| | - Christian Schimpf
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University, Linz 4040, Austria
| | - Yongheng Huo
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University, Linz 4040, Austria
- Institute for Integrative Nanosciences, IFW, Dresden 01069, Germany
- Hefei
National Laboratory for Physical Sciences at Microscale, University of Science and Technology, Shanghai 201315, China
| | - Val Zwiller
- Department
of Applied Physics, Royal Institute of Technology, Stockholm 106 91, Sweden
| | - Armando Rastelli
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University, Linz 4040, Austria
- Johannes Kepler University, Linz Institute of Technology, Linz 4040, Austria
| | - Rinaldo Trotta
- Institute of Semiconductor
and Solid State Physics, Johannes Kepler
University, Linz 4040, Austria
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16
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Orieux A, Versteegh MAM, Jöns KD, Ducci S. Semiconductor devices for entangled photon pair generation: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:076001. [PMID: 28346219 DOI: 10.1088/1361-6633/aa6955] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Entanglement is one of the most fascinating properties of quantum mechanical systems; when two particles are entangled the measurement of the properties of one of the two allows the properties of the other to be instantaneously known, whatever the distance separating them. In parallel with fundamental research on the foundations of quantum mechanics performed on complex experimental set-ups, we assist today with bourgeoning of quantum information technologies bound to exploit entanglement for a large variety of applications such as secure communications, metrology and computation. Among the different physical systems under investigation, those involving photonic components are likely to play a central role and in this context semiconductor materials exhibit a huge potential in terms of integration of several quantum components in miniature chips. In this article we review the recent progress in the development of semiconductor devices emitting entangled photons. We will present the physical processes allowing the generation of entanglement and the tools to characterize it; we will give an overview of major recent results of the last few years and highlight perspectives for future developments.
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Affiliation(s)
- Adeline Orieux
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire d'Informatique de Paris 6 (LIP6), 4 Place Jussieu, 75005 Paris, France. IRIF UMR 8243, Université Paris Diderot, Sorbonne Paris Cité, CNRS, 75013 Paris, France
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17
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Müller M, Vural H, Schneider C, Rastelli A, Schmidt OG, Höfling S, Michler P. Quantum-Dot Single-Photon Sources for Entanglement Enhanced Interferometry. PHYSICAL REVIEW LETTERS 2017; 118:257402. [PMID: 28696738 DOI: 10.1103/physrevlett.118.257402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Indexed: 06/07/2023]
Abstract
Multiphoton entangled states such as "N00N states" have attracted a lot of attention because of their possible application in high-precision, quantum enhanced phase determination. So far, N00N states have been generated in spontaneous parametric down-conversion processes and by mixing quantum and classical light on a beam splitter. Here, in contrast, we demonstrate superresolving phase measurements based on two-photon N00N states generated by quantum dot single-photon sources making use of the Hong-Ou-Mandel effect on a beam splitter. By means of pulsed resonance fluorescence of a charged exciton state, we achieve, in postselection, a quantum enhanced improvement of the precision in phase uncertainty, higher than prescribed by the standard quantum limit. An analytical description of the measurement scheme is provided, reflecting requirements, capability, and restraints of single-photon emitters in optical quantum metrology. Our results point toward the realization of a real-world quantum sensor in the near future.
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Affiliation(s)
- M Müller
- Institut für Halbleiteroptik und Funktionelle Grenzflächen, Center for Integrated Quantum Science and Technology (IQST) and SCoPE, Universität Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - H Vural
- Institut für Halbleiteroptik und Funktionelle Grenzflächen, Center for Integrated Quantum Science and Technology (IQST) and SCoPE, Universität Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - C Schneider
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - A Rastelli
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria
| | - O G Schmidt
- Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
| | - S Höfling
- Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
- SUPA, School of Physics and Astronomy, University of St. Andrews KY 16 9SS, Scotland, United Kingdom
| | - P Michler
- Institut für Halbleiteroptik und Funktionelle Grenzflächen, Center for Integrated Quantum Science and Technology (IQST) and SCoPE, Universität Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
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18
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Highly indistinguishable and strongly entangled photons from symmetric GaAs quantum dots. Nat Commun 2017; 8:15506. [PMID: 28548081 PMCID: PMC5458553 DOI: 10.1038/ncomms15506] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 04/03/2017] [Indexed: 12/25/2022] Open
Abstract
The development of scalable sources of non-classical light is fundamental to unlocking the technological potential of quantum photonics. Semiconductor quantum dots are emerging as near-optimal sources of indistinguishable single photons. However, their performance as sources of entangled-photon pairs are still modest compared to parametric down converters. Photons emitted from conventional Stranski–Krastanov InGaAs quantum dots have shown non-optimal levels of entanglement and indistinguishability. For quantum networks, both criteria must be met simultaneously. Here, we show that this is possible with a system that has received limited attention so far: GaAs quantum dots. They can emit triggered polarization-entangled photons with high purity (g(2)(0) = 0.002±0.002), high indistinguishability (0.93±0.07 for 2 ns pulse separation) and high entanglement fidelity (0.94±0.01). Our results show that GaAs might be the material of choice for quantum-dot entanglement sources in future quantum technologies. Scalable and integratable sources of entangled-photon pairs are an important building block for quantum photonic applications. Here, Huber et al. demonstrate that droplet-etched gallium arsenide quantum dots can emit highly indistinguishable photon pairs with a high degree of entanglement.
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19
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Recent advances in optical properties and applications of colloidal quantum dots under two-photon excitation. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2017.02.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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20
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Filippov S, Jansson M, Stehr JE, Palisaitis J, Persson POÅ, Ishikawa F, Chen WM, Buyanova IA. Strongly polarized quantum-dot-like light emitters embedded in GaAs/GaNAs core/shell nanowires. NANOSCALE 2016; 8:15939-15947. [PMID: 27537077 DOI: 10.1039/c6nr05168e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Recent developments in fabrication techniques and extensive investigations of the physical properties of III-V semiconductor nanowires (NWs), such as GaAs NWs, have demonstrated their potential for a multitude of advanced electronic and photonics applications. Alloying of GaAs with nitrogen can further enhance the performance and extend the device functionality via intentional defects and heterostructure engineering in GaNAs and GaAs/GaNAs coaxial NWs. In this work, it is shown that incorporation of nitrogen in GaAs NWs leads to formation of three-dimensional confining potentials caused by short-range fluctuations in the nitrogen composition, which are superimposed on long-range alloy disorder. The resulting localized states exhibit a quantum-dot like electronic structure, forming optically active states in the GaNAs shell. By directly correlating the structural and optical properties of individual NWs, it is also shown that formation of the localized states is efficient in pure zinc-blende wires and is further facilitated by structural polymorphism. The light emission from these localized states is found to be spectrally narrow (∼50-130 μeV) and is highly polarized (up to 100%) with the preferable polarization direction orthogonal to the NW axis, suggesting a preferential orientation of the localization potential. These properties of self-assembled nano-emitters embedded in the GaNAs-based nanowire structures may be attractive for potential optoelectronic applications.
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Affiliation(s)
- S Filippov
- Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden.
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21
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A quantum dot single-photon source with on-the-fly all-optical polarization control and timed emission. Nat Commun 2015; 6:8473. [PMID: 26436776 PMCID: PMC4600753 DOI: 10.1038/ncomms9473] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 08/26/2015] [Indexed: 11/12/2022] Open
Abstract
Sources of single photons are key elements for applications in quantum information science. Among the different sources available, semiconductor quantum dots excel with their integrability in semiconductor on-chip solutions and the potential that photon emission can be triggered on demand. Usually, the photon is emitted from a single-exciton ground state. Polarization of the photon and time of emission are either probabilistic or pre-determined by electronic properties of the system. Here, we study the direct two-photon emission from the biexciton. The two-photon emission is enabled by a laser pulse driving the system into a virtual state inside the band gap. From this intermediate state, the single photon of interest is then spontaneously emitted. We show that emission through this higher-order transition provides a versatile approach to generate a single photon. Through the driving laser pulse, polarization state, frequency and emission time of the photon can be controlled on-the-fly. Single photon sources are important for applications in quantum information. Here, the authors exploit higher-order transitions from a biexciton state to the ground state of a semiconductor quantum dot to emit single photons with all-optical control of their frequency, polarization and emission time.
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22
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Weiss M, Kinzel JB, Schülein FJR, Heigl M, Rudolph D, Morkötter S, Döblinger M, Bichler M, Abstreiter G, Finley JJ, Koblmüller G, Wixforth A, Krenner HJ. Dynamic acoustic control of individual optically active quantum dot-like emission centers in heterostructure nanowires. NANO LETTERS 2014; 14:2256-2264. [PMID: 24678960 DOI: 10.1021/nl4040434] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We probe and control the optical properties of emission centers forming in radial heterostructure GaAs-Al0.3Ga0.7As nanowires and show that these emitters, located in Al0.3Ga0.7As layers, can exhibit quantum-dot like characteristics. We employ a radio frequency surface acoustic wave to dynamically control their emission energy, and occupancy state on a nanosecond time scale. In the spectral oscillations, we identify unambiguous signatures arising from both the mechanical and electrical component of the surface acoustic wave. In addition, different emission lines of a single emission center exhibit pronounced anticorrelated intensity oscillations during the acoustic cycle. These arise from a dynamically triggered carrier extraction out of the emission center to a continuum in the radial heterostructure. Using finite element modeling and Wentzel-Kramers-Brillouin theory we identify quantum tunneling as the underlying mechanism. These simulation results quantitatively reproduce the observed switching and show that in our systems these emission centers are spatially separated from the continuum by >10.5 nm.
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Affiliation(s)
- Matthias Weiss
- Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg , Universitätsstraße 1, 86159 Augsburg, Germany
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23
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Jayakumar H, Predojević A, Huber T, Kauten T, Solomon GS, Weihs G. Deterministic photon pairs and coherent optical control of a single quantum dot. PHYSICAL REVIEW LETTERS 2013; 110:135505. [PMID: 23581338 DOI: 10.1103/physrevlett.110.135505] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Indexed: 06/02/2023]
Abstract
The strong confinement of semiconductor excitons in a quantum dot gives rise to atomlike behavior. The full benefit of such a structure is best observed in resonant excitation where the excited state can be deterministically populated and coherently manipulated. Because of the large refractive index and device geometry it remains challenging to observe resonantly excited emission that is free from laser scattering in III/V self-assembled quantum dots. Here we exploit the biexciton binding energy to create an extremely clean single photon source via two-photon resonant excitation of an InAs/GaAs quantum dot. We observe complete suppression of the excitation laser and multiphoton emissions. Additionally, we perform full coherent control of the ground-biexciton state qubit and observe an extended coherence time using an all-optical echo technique. The deterministic coherent photon pair creation makes this system suitable for the generation of time-bin entanglement and experiments on the interaction of photons from dissimilar sources.
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Affiliation(s)
- Harishankar Jayakumar
- Institut für Experimentalphysik, Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
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24
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Schinner GJ, Repp J, Schubert E, Rai AK, Reuter D, Wieck AD, Govorov AO, Holleitner AW, Kotthaus JP. Confinement and interaction of single indirect excitons in a voltage-controlled trap formed inside double InGaAs quantum Wells. PHYSICAL REVIEW LETTERS 2013; 110:127403. [PMID: 25166847 DOI: 10.1103/physrevlett.110.127403] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Indexed: 06/03/2023]
Abstract
Voltage-tunable quantum traps confining individual spatially indirect and long-living excitons are realized by providing a coupled double quantum well with nanoscale gates. This enables us to study the transition from confined multiexcitons down to a single, electrostatically trapped indirect exciton. In the few exciton regime, we observe discrete emission lines identified as resulting from a single dipolar exciton, a biexciton, and a triexciton, respectively. Their energetic splitting is well described by Wigner-like molecular structures reflecting the interplay of dipolar interexcitonic repulsion and spatial quantization.
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Affiliation(s)
- G J Schinner
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - J Repp
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - E Schubert
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 München, Germany
| | - A K Rai
- Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - D Reuter
- Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - A D Wieck
- Angewandte Festkörperphysik, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - A O Govorov
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 München, Germany and Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
| | - A W Holleitner
- Walter Schottky Institut and Physik-Department, Am Coulombwall 4a, Technische Universität München, D-85748 Garching, Germany
| | - J P Kotthaus
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität, Geschwister-Scholl-Platz 1, 80539 München, Germany
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25
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Wegscheider W, Abstreiter G. Von künstlichen Atomen zu Molekülen: Optische Spektroskopie an einzelnen und gekoppelten Halbleiter-Quantenpunkten. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/phbl.19980541211] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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26
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Yang S, Kiraly B, Wang WY, Shang S, Cao B, Zeng H, Zhao Y, Li W, Liu ZK, Cai W, Huang TJ. Fabrication and characterization of beaded SiC quantum rings with anomalous red spectral shift. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:5598-603. [PMID: 22911493 PMCID: PMC6453122 DOI: 10.1002/adma.201202286] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Indexed: 05/20/2023]
Affiliation(s)
- Shikuan Yang
- Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, P. R. China
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27
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Yu Y, Li MF, He JF, Zhu Y, Wang LJ, Ni HQ, He ZH, Niu ZC. Photoluminescence study of low density InAs quantum clusters grown by molecular beam epitaxy. NANOTECHNOLOGY 2012; 23:065706. [PMID: 22248719 DOI: 10.1088/0957-4484/23/6/065706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report a systematic optical spectroscopy study of low density InAs quantum clusters (QCs) grown by molecular beam epitaxy. The photoluminescence (PL) spectra show emission features of a wetting layer (WL) which contains hybridized quantum well states. The low-energy tail of the QCs' PL profile is actually an ensemble of some sharp lines, originating from the emission of different exciton states (e.g. X, X*, XX*) in a single quasi-three-dimensional (Q3D) cluster as detailed in the micro-PL spectra. The temperature dependence of PL spectra indicates photocarrier distribution and transport in the QC-WL system. Furthermore, this small InAs Q3D cluster is integrated with a distributed Bragg reflector structure, and using optical excitation creates a single photon source with the second-order correlation function of g((2))(0) = 0.31 at 16 K.
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Affiliation(s)
- Ying Yu
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, People's Republic of China.
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28
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Ghali M, Ohtani K, Ohno Y, Ohno H. Generation and control of polarization-entangled photons from GaAs island quantum dots by an electric field. Nat Commun 2012; 3:661. [PMID: 22314357 PMCID: PMC3293408 DOI: 10.1038/ncomms1657] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 12/21/2011] [Indexed: 11/09/2022] Open
Abstract
Semiconductor quantum dots are potential sources for generating polarization-entangled photons efficiently. The main prerequisite for such generation based on biexciton-exciton cascaded emission is to control the exciton fine-structure splitting. Among various techniques investigated for this purpose, an electric field is a promising means to facilitate the integration into optoelectronic devices. Here we demonstrate the generation of polarization-entangled photons from single GaAs quantum dots by an electric field. In contrast to previous studies, which were limited to In(Ga)As quantum dots, GaAs island quantum dots formed by a thickness fluctuation were used because they exhibit a larger oscillator strength and emit light with a shorter wavelength. A forward voltage was applied to a Schottky diode to control the fine-structure splitting. We observed a decrease and suppression in the fine-structure splitting of the studied single quantum dot with the field, which enabled us to generate polarization-entangled photons with a high fidelity of 0.72 ± 0.05.
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Affiliation(s)
- Mohsen Ghali
- Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
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Wunsch B, Zinner NT, Mekhov IB, Huang SJ, Wang DW, Demler E. Few-body bound states in dipolar gases and their detection. PHYSICAL REVIEW LETTERS 2011; 107:073201. [PMID: 21902390 DOI: 10.1103/physrevlett.107.073201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Indexed: 05/31/2023]
Abstract
We consider dipolar interactions between heteronuclear molecules in a low-dimensional setup consisting of two one-dimensional tubes. We demonstrate that attraction between molecules in different tubes can overcome intratube repulsion and complexes with several molecules in the same tube are stable. In situ detection schemes of the few-body complexes are proposed. We discuss extensions to many tubes and layers, and outline the implications on many-body physics.
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Affiliation(s)
- B Wunsch
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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30
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Heiss M, Ketterer B, Uccelli E, Morante JR, Arbiol J, Fontcuberta i Morral A. In(Ga)As quantum dot formation on group-III assisted catalyst-free InGaAs nanowires. NANOTECHNOLOGY 2011; 22:195601. [PMID: 21430322 DOI: 10.1088/0957-4484/22/19/195601] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Growth of GaAs and In(x)Ga(1-x)As nanowires by the group-III assisted molecular beam epitaxy growth method on (001)GaAs/SiO(2) substrates is studied in dependence on growth temperature, with the objective of maximizing the indium incorporation. Nanowire growth was achieved for growth temperatures as low as 550 °C. The incorporation of indium was studied by low temperature micro-photoluminescence spectroscopy, Raman spectroscopy and electron energy loss spectroscopy. The results show that the incorporation of indium achieved by lowering the growth temperature does not have the effect of increasing the indium concentration in the bulk of the nanowire, which is limited to 3-5%. For growth temperatures below 575 °C, indium rich regions form at the surface of the nanowires as a consequence of the radial growth. This results in the formation of quantum dots, which exhibit spectrally narrow luminescence.
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Affiliation(s)
- Martin Heiss
- Laboratoire des Matériaux Semiconducteurs, Institut des Matériaux, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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31
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Völk S, Schülein FJR, Knall F, Reuter D, Wieck AD, Truong TA, Kim H, Petroff PM, Wixforth A, Krenner HJ. Enhanced sequential carrier capture into individual quantum dots and quantum posts controlled by surface acoustic waves. NANO LETTERS 2010; 10:3399-3407. [PMID: 20722408 DOI: 10.1021/nl1013053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Individual self-assembled quantum dots and quantum posts are studied under the influence of a surface acoustic wave. In optical experiments we observe an acoustically induced switching of the occupancy of the nanostructures along with an overall increase of the emission intensity. For quantum posts, switching occurs continuously from predominantly charged excitons (dissimilar number of electrons and holes) to neutral excitons (same number of electrons and holes) and is independent of whether the surface acoustic wave amplitude is increased or decreased. For quantum dots, switching is nonmonotonic and shows a pronounced hysteresis on the amplitude sweep direction. Moreover, emission of positively charged and neutral excitons is observed at high surface acoustic wave amplitudes. These findings are explained by carrier trapping and localization in the thin and disordered two-dimensional wetting layer on top of which quantum dots nucleate. This limitation can be overcome for quantum posts where acoustically induced charge transport is highly efficient in a wide lateral matrix-quantum well.
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Affiliation(s)
- Stefan Völk
- Lehrstuhl für Experimentalphysik 1, Universität Augsburg, Universitätsstrasse 1, 86159 Augsburg, Germany
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32
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Lee HS, Rastelli A, Benyoucef M, Ding F, Kim TW, Park HL, Schmidt OG. Microphotoluminescence spectroscopy of single CdTe/ZnTe quantum dots grown on Si001 substrates. NANOTECHNOLOGY 2009; 20:075705. [PMID: 19417433 DOI: 10.1088/0957-4484/20/7/075705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have studied the emission properties of single CdTe/ZnTe quantum dots (QDs) grown on Si(001) substrates by using molecular beam epitaxy and atomic layer epitaxy. The good quality of the QDs is attested by the resolution-limited emission, negligible background and absence of measurable spectral jitter or blinking. Power-dependent, polarization-dependent, and temperature-dependent microphotoluminescence spectroscopy measurements were performed to identify the exciton, the biexciton, and two oppositely charged excitons in the emission spectra of single QDs.
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Affiliation(s)
- H S Lee
- Institute for Integrative Nanosciences, IFW Dresden, Dresden, Germany.
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33
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Dousse A, Lanco L, Suffczyński J, Semenova E, Miard A, Lemaître A, Sagnes I, Roblin C, Bloch J, Senellart P. Controlled light-matter coupling for a single quantum dot embedded in a pillar microcavity using far-field optical lithography. PHYSICAL REVIEW LETTERS 2008; 101:267404. [PMID: 19437672 DOI: 10.1103/physrevlett.101.267404] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Using far-field optical lithography, a single quantum dot is positioned within a pillar microcavity with a 50 nm accuracy. The lithography is performed in situ at 10 K while measuring the quantum dot emission. Deterministic spectral and spatial matching of the cavity-dot system is achieved in a single step process and evidenced by the observation of strong Purcell effect. Deterministic coupling of two quantum dots to the same optical mode is achieved, a milestone for quantum computing.
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Affiliation(s)
- A Dousse
- Laboratoire de Photonique et Nanostructures, LPN/CNRS, Route de Nozay, 91460 Marcoussis, France
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34
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Okada T, Komori K, Goshima K, Yamauchi S, Morohashi I, Sugaya T, Ogura M, Tsurumachi N. Development of high resolution Michelson interferometer for stable phase-locked ultrashort pulse pair generation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:103101. [PMID: 19044696 DOI: 10.1063/1.2993980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We developed a high resolution Michelson interferometer with a two-frequency He-Ne laser positioning system in order to stabilize the relative phase of a pulse pair. The control resolution corresponded to a 12 as time resolution or a phase of 1.5 degrees at 900 nm. This high resolution Michelson interferometer can generate a phase-locked pulse pair either with a specific relative phase such as 0 or pi radians or with an arbitrary phase. Coherent control of an InAs self-assembled quantum dot was demonstrated using the high resolution Michelson interferometer with a microspectroscopy system.
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Affiliation(s)
- Takumi Okada
- Student Project Center, Tokai University, 1117 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
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35
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Fontcuberta i Morral A, Spirkoska D, Arbiol J, Heigoldt M, Ramon Morante J, Abstreiter G. Prismatic quantum heterostructures synthesized on molecular-beam epitaxy GaAs nanowires. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2008; 4:899-903. [PMID: 18504720 DOI: 10.1002/smll.200701091] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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36
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Högele A, Galland C, Winger M, Imamoğlu A. Photon antibunching in the photoluminescence spectra of a single carbon nanotube. PHYSICAL REVIEW LETTERS 2008; 100:217401. [PMID: 18518631 DOI: 10.1103/physrevlett.100.217401] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Indexed: 05/26/2023]
Abstract
We report the first observation of photon antibunching in the photoluminescence from single carbon nanotubes. The emergence of a fast luminescence decay component under strong optical excitation indicates that Auger processes are partially responsible for inhibiting two-photon generation. Additionally, the presence of exciton localization at low temperatures ensures that nanotubes emit photons predominantly one by one. The fact that multiphoton emission probability can be smaller than 5% suggests that carbon nanotubes could be used as a source of single photons for applications in quantum cryptography.
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Affiliation(s)
- Alexander Högele
- Institute of Quantum Electronics, ETH Hönggerberg, Wolfgang-Pauli-Strasse 16, CH-8093 Zürich, Switzerland
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37
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Coolen L, Brokmann X, Spinicelli P, Hermier JP. Emission characterization of a single CdSe-ZnS nanocrystal with high temporal and spectral resolution by photon-correlation Fourier spectroscopy. PHYSICAL REVIEW LETTERS 2008; 100:027403. [PMID: 18232922 DOI: 10.1103/physrevlett.100.027403] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Indexed: 05/25/2023]
Abstract
We report a spectroscopic study of single colloidal CdSe/ZnS nanocrystals at low temperature. We use photon-correlation Fourier spectroscopy, a technique based on measuring the correlations of the intensities detected at the outputs of a Michelson interferometer. Spectral diffusion over a few microeV is evidenced, on a typical time scale of 200 micros. A time resolution as high as 20 micros is obtained, and an upper limit of 6.5 microeV emission linewidth is measured, corresponding to a coherence time of at least 200 ps, similar to the values for epitaxial quantum dots.
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Affiliation(s)
- L Coolen
- Laboratoire Kastler Brossel, Ecole normale supérieure, Université Pierre et Marie Curie Paris 6, CNRS, 24 rue Lhomond, 75231 Paris Cedex 05, France
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38
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Zrenner A, Stufler S, Ester P, Bichler M. Coherent Properties of Quantum Dot Two-Level Systems. Isr J Chem 2006. [DOI: 10.1560/ijc_46_4_349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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39
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Akimov IA, Andrews JT, Henneberger F. Stimulated emission from the biexciton in a single self-assembled II-VI quantum dot. PHYSICAL REVIEW LETTERS 2006; 96:067401. [PMID: 16606045 DOI: 10.1103/physrevlett.96.067401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2005] [Indexed: 05/08/2023]
Abstract
Using two-photon excitation, stimulated emission from the biexciton state in a single CdSe/ZnSe quantum dot is observed in a two-pulse configuration. We directly time resolve the emission-absorption characteristics and verify the potential for laser action. By setting the polarization of the stimulation pulse, the recombination path of the biexciton and, by this, the state of the photons emitted in the decay cascade is controlled. We elaborate also the coherent response and address entanglement and disentanglement of the exciton-biexciton system.
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Affiliation(s)
- I A Akimov
- Institut für Physik, Humboldt Universität zu Berlin, Newtonstrasse 15, 12489 Berlin, Germany
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40
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41
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Feltrin A, Michelini F, Staehli JL, Deveaud B, Savona V, Toquant J, Wang XL, Ogura M. Localization-dependent photoluminescence spectrum of biexcitons in semiconductor quantum wires. PHYSICAL REVIEW LETTERS 2005; 95:177404. [PMID: 16383868 DOI: 10.1103/physrevlett.95.177404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Indexed: 05/05/2023]
Abstract
We study exciton and biexciton spectra in disordered semiconductor quantum wires by means of nanophotoluminescence spectroscopy. We demonstrate a close link between the exciton localization length along the wire and the occurrence of a biexciton spectral line. The biexciton signature appears only if the corresponding exciton state extends over more than a few tens of nanometers. We also measure a nonmonotonous variation of the biexciton binding energy with decreasing exciton localization length. This behavior is quantitatively well reproduced by the solution of the single-band Schrödinger equation of the four-particle problem in a one-dimensional confining potential.
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Affiliation(s)
- A Feltrin
- Institut de Photonique et d'Electronique Quantiques, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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42
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Yoshie T, Scherer A, Hendrickson J, Khitrova G, Gibbs HM, Rupper G, Ell C, Shchekin OB, Deppe DG. Vacuum Rabi splitting with a single quantum dot in a photonic crystal nanocavity. Nature 2004; 432:200-3. [PMID: 15538363 DOI: 10.1038/nature03119] [Citation(s) in RCA: 507] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2004] [Accepted: 10/19/2004] [Indexed: 11/09/2022]
Abstract
Cavity quantum electrodynamics (QED) systems allow the study of a variety of fundamental quantum-optics phenomena, such as entanglement, quantum decoherence and the quantum-classical boundary. Such systems also provide test beds for quantum information science. Nearly all strongly coupled cavity QED experiments have used a single atom in a high-quality-factor (high-Q) cavity. Here we report the experimental realization of a strongly coupled system in the solid state: a single quantum dot embedded in the spacer of a nanocavity, showing vacuum-field Rabi splitting exceeding the decoherence linewidths of both the nanocavity and the quantum dot. This requires a small-volume cavity and an atomic-like two-level system. The photonic crystal slab nanocavity--which traps photons when a defect is introduced inside the two-dimensional photonic bandgap by leaving out one or more holes--has both high Q and small modal volume V, as required for strong light-matter interactions. The quantum dot has two discrete energy levels with a transition dipole moment much larger than that of an atom, and it is fixed in the nanocavity during growth.
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Affiliation(s)
- T Yoshie
- Electrical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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43
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Beham E, Betz M, Trumm S, Kroutvar M, Ducommun Y, Krenner HJ, Bichler M, Leitenstorfer A, Finley JJ, Zrenner A, Abstreiter G. Physics and applications of self-assembled quantum dots. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/pssc.200404764] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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44
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Flissikowski T, Betke A, Akimov IA, Henneberger F. Two-photon coherent control of a single quantum dot. PHYSICAL REVIEW LETTERS 2004; 92:227401. [PMID: 15245258 DOI: 10.1103/physrevlett.92.227401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2004] [Indexed: 05/24/2023]
Abstract
We report on two-photon coherent control of the biexciton state in single Stranski-Krastanov CdSe quantum dots. Clear interference patterns are observed at twice the optical frequency. The decay of the interference contrast is nonexponential and caused by a dynamical inhomogeneous broadening of the energy levels due to long-term fluctuations in the dot environment.
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Affiliation(s)
- T Flissikowski
- Institut für Physik, Humboldt Universität zu Berlin, Newtonstrasse 15, 12489 Berlin, Germany
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45
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Rastelli A, Stufler S, Schliwa A, Songmuang R, Manzano C, Costantini G, Kern K, Zrenner A, Bimberg D, Schmidt OG. Hierarchical self-assembly of GaAs/AlGaAs quantum dots. PHYSICAL REVIEW LETTERS 2004; 92:166104. [PMID: 15169246 DOI: 10.1103/physrevlett.92.166104] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2003] [Indexed: 05/24/2023]
Abstract
A novel structure containing self-assembled, unstrained GaAs quantum dots is obtained by combining solid-source molecular beam epitaxy and atomic-layer precise in situ etching. Photo-luminescence (PL) spectroscopy reveals light emission with very narrow inhomogeneous broadening and clearly resolved excited states at high excitation intensity. The dot morphology is determined by scanning probe microscopy and, combined with single band and eight-band k.p theory calculations, is used to interpret PL and single-dot spectra with no adjustable structural parameter.
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Affiliation(s)
- A Rastelli
- Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
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46
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Unold T, Mueller K, Lienau C, Elsaesser T, Wieck AD. Optical Stark effect in a quantum dot: ultrafast control of single exciton polarizations. PHYSICAL REVIEW LETTERS 2004; 92:157401. [PMID: 15169317 DOI: 10.1103/physrevlett.92.157401] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2003] [Indexed: 05/24/2023]
Abstract
We report the first experimental study of the optical Stark effect in single semiconductor quantum dots (QD). For below band gap excitation, two-color pump-probe spectra show dispersive line shapes caused by a light-induced blueshift of the excitonic resonance. The line shape depends strongly on the excitation field strength and is determined by the pump-induced phase shift of the coherent QD polarization. Transient spectral oscillations can be understood as rotations of the QD polarization phase with negligible population change. Ultrafast control of the QD polarization is demonstrated.
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Affiliation(s)
- Thomas Unold
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany
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47
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Lienau C. Ultrafast near-field spectroscopy of single semiconductor quantum dots. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2004; 362:861-879. [PMID: 15306498 DOI: 10.1098/rsta.2003.1353] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Excitonic and spin excitations of single semiconductor quantum dots (QDs) currently attract attention as possible candidates for solid-state-based implementations of quantum logic devices. Due to their rather short decoherence times in the picosecond to nanosecond range, such implementations rely on using ultrafast optical pulses to probe and control coherent polarizations. We combine ultrafast spectroscopy and near-field microscopy to probe the nonlinear optical response of a single QD on a femtosecond time-scale. Transient reflectivity spectra show pronounced oscillations around the QD exciton line. These oscillations reflect phase-disturbing Coulomb interactions between the excitonic QD polarization and continuum excitations. The results show that although semiconductor QDs resemble in many respects atomic systems, Coulomb many-body interactions can contribute significantly to their optical nonlinearities on ultrashort time-scales.
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Affiliation(s)
- Christoph Lienau
- Max-Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, 12489 Berlin, Germany.
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48
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Matsuda K, Saiki T, Nomura S, Mihara M, Aoyagi Y, Nair S, Takagahara T. Near-field optical mapping of exciton wave functions in a GaAs quantum dot. PHYSICAL REVIEW LETTERS 2003; 91:177401. [PMID: 14611375 DOI: 10.1103/physrevlett.91.177401] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2003] [Indexed: 05/24/2023]
Abstract
Near-field photoluminescence imaging spectroscopy of naturally occurring GaAs quantum dots (QDs) is presented. We successfully mapped out center-of -mass wave functions of an exciton confined in a GaAs QD in real space due to the enhancement of spatial resolution up to 30 nm. As a consequence, we discovered that the spatial profile of the exciton emission, which reflects the shape of a monolayer-high island, differs from that of biexciton emission, due to different distributions of the polarization field for the exciton and biexciton recombinations. This novel technique can be extensively applied to wave function engineering in the design and the fabrication of quantum devices.
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Affiliation(s)
- K Matsuda
- Kanagawa Academy of Science and Technology, 3-2-1 Sakado, Takatsu, Kawasaki, Japan.
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49
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Li X, Wu Y, Steel D, Gammon D, Stievater TH, Katzer DS, Park D, Piermarocchi C, Sham LJ. An all-optical quantum gate in a semiconductor quantum dot. Science 2003; 301:809-11. [PMID: 12907794 DOI: 10.1126/science.1083800] [Citation(s) in RCA: 190] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We report coherent optical control of a biexciton (two electron-hole pairs), confined in a single quantum dot, that shows coherent oscillations similar to the excited-state Rabi flopping in an isolated atom. The pulse control of the biexciton dynamics, combined with previously demonstrated control of the single-exciton Rabi rotation, serves as the physical basis for a two-bit conditional quantum logic gate. The truth table of the gate shows the features of an all-optical quantum gate with interacting yet distinguishable excitons as qubits. Evaluation of the fidelity yields a value of 0.7 for the gate operation. Such experimental capability is essential to a scheme for scalable quantum computation by means of the optical control of spin qubits in dots.
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Affiliation(s)
- Xiaoqin Li
- Frontiers in Optical Coherent and Ultrafast Science (FOCUS), Harrison M. Randall Laboratory of Physics, The University of Michigan, Ann Arbor, Michigan 48109-1120, USA
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50
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Zrenner A, Beham E, Stufler S, Findeis F, Bichler M, Abstreiter G. Coherent properties of a two-level system based on a quantum-dot photodiode. Nature 2002; 418:612-4. [PMID: 12167853 DOI: 10.1038/nature00912] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Present-day information technology is based mainly on incoherent processes in conventional semiconductor devices. To realize concepts for future quantum information technologies, which are based on coherent phenomena, a new type of 'hardware' is required. Semiconductor quantum dots are promising candidates for the basic device units for quantum information processing. One approach is to exploit optical excitations (excitons) in quantum dots. It has already been demonstrated that coherent manipulation between two excitonic energy levels--via so-called Rabi oscillations--can be achieved in single quantum dots by applying electromagnetic fields. Here we make use of this effect by placing an InGaAs quantum dot in a photodiode, which essentially connects it to an electric circuit. We demonstrate that coherent optical excitations in the quantum-dot two-level system can be converted into deterministic photocurrents. For optical excitation with so-called pi-pulses, which completely invert the two-level system, the current is given by I = fe, where f is the repetition frequency of the experiment and e is the elementary charge. We find that this device can function as an optically triggered single-electron turnstile.
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Affiliation(s)
- A Zrenner
- Walter Schottky Institut, Technische Universität München, Am Coulombwall, D-85748 Garching, Germany.
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