1
|
Roy P, Pandey A. Engineering quantum dots for improved single photon emission statistics. J Chem Phys 2024; 160:204707. [PMID: 38785288 DOI: 10.1063/5.0205113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 05/06/2024] [Indexed: 05/25/2024] Open
Abstract
High fidelity single photon sources are required for the implementation of quantum information processing and communications protocols. Although colloidal quantum dots (CQDs) are single photon sources, their efficacy is limited by their tendency to show finite multiphoton emission at higher excitation powers. Here, we show that wave function engineering of CQDs enables the realization of emitters with significantly improved single photon emission performance. We study the ZnS/CdSe/CdS system. It is shown that this system offers significantly improved probabilities of single photon emission. While conventional CQDs such as CdSe/CdS exhibit a g2(0) > 0.5 ± 0.02 at ⟨N⟩ = 2.17, ZnS/CdSe/CdS show a greatly improved g2(0) ≈ 0.04 ± 0.01. Improved single photon emission performance encourages the use of colloidal materials as quantum light sources in emerging quantum devices.
Collapse
Affiliation(s)
- Parna Roy
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Anshu Pandey
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| |
Collapse
|
2
|
Burakowski M, Holewa P, Mrowiński P, Sakanas A, Musiał A, Sȩk G, Yvind K, Semenova E, Syperek M. Heterogeneous integration of single InAs/InP quantum dots with the SOI chip using direct bonding. OPTICS EXPRESS 2024; 32:10874-10886. [PMID: 38570950 DOI: 10.1364/oe.515223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/09/2024] [Indexed: 04/05/2024]
Abstract
Quantum information processing with photons in small-footprint and highly integrated silicon-based photonic chips requires incorporating non-classical light sources. In this respect, self-assembled III-V semiconductor quantum dots (QDs) are an attractive solution, however, they must be combined with the silicon platform. Here, by utilizing the large-area direct bonding technique, we demonstrate the hybridization of InP and SOI chips, which allows for coupling single photons to the SOI chip interior, offering cost-effective scalability in setting up a multi-source environment for quantum photonic chips. We fabricate devices consisting of self-assembled InAs QDs embedded in the tapered InP waveguide (WG) positioned over the SOI-defined Si WG. Focusing on devices generating light in the telecom C-band compatible with the low-loss optical fiber networks, we demonstrate the light coupling between InP and SOI platforms by observing photons outcoupled at the InP-made circular Bragg grating outcoupler fabricated at the end of an 80 µm-long Si WG, and at the cleaved edge of the Si WG. Finally, for a device with suppressed multi-photon generation events exhibiting 80% single photon generation purity, we measure the photon number outcoupled at the cleaved facet of the Si WG. We estimate the directional on-chip photon coupling between the source and the Si WG to 5.1%.
Collapse
|
3
|
Ramachandran A, Wilbur GR, Mathew R, Mason A, O'Neal S, Deppe DG, Hall KC. Robust parallel laser driving of quantum dots for multiplexing of quantum light sources. Sci Rep 2024; 14:5356. [PMID: 38438449 PMCID: PMC10912409 DOI: 10.1038/s41598-024-55634-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 02/23/2024] [Indexed: 03/06/2024] Open
Abstract
Deterministic sources of quantum light (i.e. single photons or pairs of entangled photons) are required for a whole host of applications in quantum technology, including quantum imaging, quantum cryptography and the long-distance transfer of quantum information in future quantum networks. Semiconductor quantum dots are ideal candidates for solid-state quantum emitters as these artificial atoms have large dipole moments and a quantum confined energy level structure, enabling the realization of single photon sources with high repetition rates and high single photon purity. Quantum dots may also be triggered using a laser pulse for on-demand operation. The naturally-occurring size variations in ensembles of quantum dots offers the potential to increase the bandwidth of quantum communication systems through wavelength-division multiplexing, but conventional laser triggering schemes based on Rabi rotations are ineffective when applied to inequivalent emitters. Here we report the demonstration of the simultaneous triggering of >10 quantum dots using adiabatic rapid passage. We show that high-fidelity quantum state inversion is possible in a system of quantum dots with a 15 meV range of optical transition energies using a single broadband, chirped laser pulse, laying the foundation for high-bandwidth, multiplexed quantum networks.
Collapse
Affiliation(s)
- Ajan Ramachandran
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Grant R Wilbur
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Reuble Mathew
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Allister Mason
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Sabine O'Neal
- The College of Optics and Photonics, University of Central Florida, Orlando, FL, 32816-2700, USA
- IMEC, Kissimmee, FL, 34744, USA
| | - Dennis G Deppe
- The College of Optics and Photonics, University of Central Florida, Orlando, FL, 32816-2700, USA
- SdPhotonics, Richardson, TX, 75081, USA
| | - Kimberley C Hall
- Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, B3H 4R2, Canada.
| |
Collapse
|
4
|
Phillips CL, Brash AJ, Godsland M, Martin NJ, Foster A, Tomlinson A, Dost R, Babazadeh N, Sala EM, Wilson L, Heffernan J, Skolnick MS, Fox AM. Purcell-enhanced single photons at telecom wavelengths from a quantum dot in a photonic crystal cavity. Sci Rep 2024; 14:4450. [PMID: 38396018 DOI: 10.1038/s41598-024-55024-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 02/16/2024] [Indexed: 02/25/2024] Open
Abstract
Quantum dots are promising candidates for telecom single photon sources due to their tunable emission across the different low-loss telecommunications bands, making them compatible with existing fiber networks. Their suitability for integration into photonic structures allows for enhanced brightness through the Purcell effect, supporting efficient quantum communication technologies. Our work focuses on InAs/InP QDs created via droplet epitaxy MOVPE to operate within the telecoms C-band. We observe a short radiative lifetime of 340 ps, arising from a Purcell factor of 5, owing to integration of the QD within a low-mode-volume photonic crystal cavity. Through in-situ control of the sample temperature, we show both temperature tuning of the QD's emission wavelength and a preserved single photon emission purity at temperatures up to 25K. These findings suggest the viability of QD-based, cryogen-free C-band single photon sources, supporting applicability in quantum communication technologies.
Collapse
Affiliation(s)
| | - Alistair J Brash
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - Max Godsland
- EPSRC National Epitaxy Facility, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
| | - Nicholas J Martin
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - Andrew Foster
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - Anna Tomlinson
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - René Dost
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - Nasser Babazadeh
- EPSRC National Epitaxy Facility, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
| | - Elisa M Sala
- EPSRC National Epitaxy Facility, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
| | - Luke Wilson
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - Jon Heffernan
- EPSRC National Epitaxy Facility, Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
| | - Maurice S Skolnick
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - A Mark Fox
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| |
Collapse
|
5
|
Vajner D, Holewa P, Zięba-Ostój E, Wasiluk M, von Helversen M, Sakanas A, Huck A, Yvind K, Gregersen N, Musiał A, Syperek M, Semenova E, Heindel T. On-Demand Generation of Indistinguishable Photons in the Telecom C-Band Using Quantum Dot Devices. ACS PHOTONICS 2024; 11:339-347. [PMID: 38405394 PMCID: PMC10885198 DOI: 10.1021/acsphotonics.3c00973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 12/22/2023] [Accepted: 12/26/2023] [Indexed: 02/27/2024]
Abstract
Semiconductor quantum dots (QDs) enable the generation of single and entangled photons, which are useful for various applications in photonic quantum technologies. Specifically for quantum communication via fiber-optical networks, operation in the telecom C-band centered around 1550 nm is ideal. The direct generation of QD-photons in this spectral range with high quantum-optical quality, however, remained challenging. Here, we demonstrate the coherent on-demand generation of indistinguishable photons in the telecom C-band from single QD devices consisting of InAs/InP QD-mesa structures heterogeneously integrated with a metallic reflector on a silicon wafer. Using pulsed two-photon resonant excitation of the biexciton-exciton radiative cascade, we observe Rabi rotations up to pulse areas of 4π and a high single-photon purity in terms of g(2)(0) = 0.005(1) and 0.015(1) for exciton and biexciton photons, respectively. Applying two independent experimental methods, based on fitting Rabi rotations in the emission intensity and performing photon cross-correlation measurements, we consistently obtain preparation fidelities at the π-pulse exceeding 80%. Finally, performing Hong-Ou-Mandel-type two-photon interference experiments, we obtain a photon-indistinguishability of the full photon wave packet of up to 35(3)%, representing a significant advancement in the photon-indistinguishability of single photons emitted directly in the telecom C-band.
Collapse
Affiliation(s)
- Daniel
A. Vajner
- Institute
of Solid State Physics, Technical University
of Berlin, 10623 Berlin, Germany
| | - Paweł Holewa
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
- DTU
Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark
- NanoPhoton
− Center for Nanophotonics, Technical
University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Emilia Zięba-Ostój
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Maja Wasiluk
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Martin von Helversen
- Institute
of Solid State Physics, Technical University
of Berlin, 10623 Berlin, Germany
| | - Aurimas Sakanas
- DTU
Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Alexander Huck
- Center
for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Kresten Yvind
- DTU
Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark
- NanoPhoton
− Center for Nanophotonics, Technical
University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Niels Gregersen
- DTU
Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Anna Musiał
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Marcin Syperek
- Department
of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Elizaveta Semenova
- DTU
Electro, Department of Electrical and Photonics Engineering, Technical University of Denmark, Kongens Lyngby 2800, Denmark
- NanoPhoton
− Center for Nanophotonics, Technical
University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Tobias Heindel
- Institute
of Solid State Physics, Technical University
of Berlin, 10623 Berlin, Germany
| |
Collapse
|
6
|
Wang K, Li W, Liao Y, Li J, Chen R, Chen Q, Shi B, Kim DH, Park JH, Zhang Y, Zhou X, Wu C, Liu Z, Guo T, Kim TW. Electron Oscillation-Induced Splitting Electroluminescence from Nano-LEDs for Device-Level Encryption. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2306065. [PMID: 37560962 DOI: 10.1002/adma.202306065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/31/2023] [Indexed: 08/11/2023]
Abstract
Data security is a major concern in digital age, which generally relies on algorithm-based mathematical encryption. Recently, encryption techniques based on physical principles are emerging and being developed, leading to the new generation of encryption moving from mathematics to the intersection of mathematics and physics. Here, device-level encryption with ideal security is ingeniously achieved using modulation of the electron-hole radiative recombination in a GaN-light-emitting diode (LED). When a nano-LED is driven in the non-carrier injection mode, the oscillation of confined electrons can split what should be a single light pulse into multiple pulses. The morphology (amplitude, shape, and pulse number) of those history-dependent multiple pulses that act as carriers for transmitted digital information depends highly on the parameters of the driving signals, which makes those signals mathematically uncrackable and can increase the volume and security of transmitted information. Moreover, a hardware and software platform are designed to demonstrate the encrypted data transmission based on the device-level encryption method, enabling recognition of the entire ASCII code table. The device-level encryption based on splitting electroluminescence provides an encryption method during the conversion process of digital signals to optical signals and can improve the security of LED-based communication.
Collapse
Affiliation(s)
- Kun Wang
- College of Physics and Information Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Wenhao Li
- College of Physics and Information Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Yitao Liao
- College of Physics and Information Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Junlong Li
- College of Physics and Information Engineering, Fuzhou University, Fuzhou, 350108, China
| | - Rong Chen
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, 350108, China
| | - Qi Chen
- Research and Development Center for Semiconductor Lighting Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
| | - Bo Shi
- Research and Development Center for Semiconductor Lighting Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
| | - Dae Hun Kim
- Department of Electronic and Computer Engineering, Hanyang University, Seoul, 133-791, South Korea
| | - Jae Hyeon Park
- Department of Electronic and Computer Engineering, Hanyang University, Seoul, 133-791, South Korea
| | - Yongai Zhang
- College of Physics and Information Engineering, Fuzhou University, Fuzhou, 350108, China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, 350108, China
| | - Xiongtu Zhou
- College of Physics and Information Engineering, Fuzhou University, Fuzhou, 350108, China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, 350108, China
| | - Chaoxing Wu
- College of Physics and Information Engineering, Fuzhou University, Fuzhou, 350108, China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, 350108, China
| | - Zhiqiang Liu
- Research and Development Center for Semiconductor Lighting Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
| | - Tailiang Guo
- College of Physics and Information Engineering, Fuzhou University, Fuzhou, 350108, China
- Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China, Fuzhou, 350108, China
| | - Tae Whan Kim
- Department of Electronic and Computer Engineering, Hanyang University, Seoul, 133-791, South Korea
| |
Collapse
|
7
|
Wells L, Müller T, Stevenson RM, Skiba-Szymanska J, Ritchie DA, Shields AJ. Coherent light scattering from a telecom C-band quantum dot. Nat Commun 2023; 14:8371. [PMID: 38102132 PMCID: PMC10724139 DOI: 10.1038/s41467-023-43757-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 11/17/2023] [Indexed: 12/17/2023] Open
Abstract
Quantum networks have the potential to transform secure communication via quantum key distribution and enable novel concepts in distributed quantum computing and sensing. Coherent quantum light generation at telecom wavelengths is fundamental for fibre-based network implementations, but Fourier-limited emission and subnatural linewidth photons have so far only been reported from systems operating in the visible to near-infrared wavelength range. Here, we use InAs/InP quantum dots to demonstrate photons with coherence times much longer than the Fourier limit at telecom wavelength via elastic scattering of excitation laser photons. Further, we show that even the inelastically scattered photons have coherence times within the error bars of the Fourier limit. Finally, we make direct use of the minimal attenuation in fibre for these photons by measuring two-photon interference after 25 km of fibre, demonstrating finite interference visibility for photons emitted about 100,000 excitation cycles apart.
Collapse
Affiliation(s)
- L Wells
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - T Müller
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK.
| | - R M Stevenson
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK
| | - J Skiba-Szymanska
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK
| | - D A Ritchie
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - A J Shields
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK
| |
Collapse
|
8
|
Yu Y, Liu S, Lee CM, Michler P, Reitzenstein S, Srinivasan K, Waks E, Liu J. Telecom-band quantum dot technologies for long-distance quantum networks. NATURE NANOTECHNOLOGY 2023; 18:1389-1400. [PMID: 38049595 DOI: 10.1038/s41565-023-01528-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 09/15/2023] [Indexed: 12/06/2023]
Abstract
A future quantum internet is expected to generate, distribute, store and process quantum bits (qubits) over the world by linking different quantum nodes via quantum states of light. To facilitate long-haul operations, quantum repeaters must operate at telecom wavelengths to take advantage of both the low-loss optical fibre network and the established technologies of modern optical communications. Semiconductor quantum dots have thus far shown exceptional performance as key elements for quantum repeaters, such as quantum light sources and spin-photon interfaces, but only in the near-infrared regime. Therefore, the development of high-performance telecom-band quantum dot devices is highly desirable for a future solid-state quantum internet based on fibre networks. In this Review, we present the physics and technological developments towards epitaxial quantum dot devices emitting in the telecom O- and C-bands for quantum networks, considering both advanced epitaxial growth for direct telecom emission and quantum frequency conversion for telecom-band down-conversion of near-infrared quantum dot devices. We also discuss the challenges and opportunities for future realization of telecom quantum dot devices with improved performance and expanded functionality through hybrid integration.
Collapse
Affiliation(s)
- Ying Yu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, School of Physics, Sun Yat-sen University, Guangzhou, China
| | - Shunfa Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, School of Physics, Sun Yat-sen University, Guangzhou, China
| | - Chang-Min Lee
- Department of Electrical and Computer Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD, USA
| | - Peter Michler
- Institut für Halbleiteroptik und Funktionelle Grenzflächen (IHFG), Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Stuttgart, Germany
| | - Stephan Reitzenstein
- Institute of Solid State Physics, Technische Universität Berlin, Berlin, Germany
| | - Kartik Srinivasan
- Joint Quantum Institute, NIST/University of Maryland, College Park, MD, USA
- Microsystems and Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, USA
| | - Edo Waks
- Department of Electrical and Computer Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD, USA
- Joint Quantum Institute, NIST/University of Maryland, College Park, MD, USA
| | - Jin Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, School of Physics, Sun Yat-sen University, Guangzhou, China.
| |
Collapse
|
9
|
Zhu D, Bahmani Jalali H, Saleh G, Di Stasio F, Prato M, Polykarpou N, Othonos A, Christodoulou S, Ivanov YP, Divitini G, Infante I, De Trizio L, Manna L. Boosting the Photoluminescence Efficiency of InAs Nanocrystals Synthesized with Aminoarsine via a ZnSe Thick-Shell Overgrowth. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2303621. [PMID: 37243572 DOI: 10.1002/adma.202303621] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/18/2023] [Indexed: 05/29/2023]
Abstract
InAs-based nanocrystals can enable restriction of hazardous substances (RoHS) compliant optoelectronic devices, but their photoluminescence efficiency needs improvement. We report an optimized synthesis of InAs@ZnSe core@shell nanocrystals allowing to tune the ZnSe shell thickness up to seven mono-layers (ML) and to boost the emission, reaching a quantum yield of ≈70% at ≈900 nm. It is demonstrated that a high quantum yield can be attained when the shell thickness is at least ≈3ML. Notably, the photoluminescence lifetimeshows only a minor variation as a function of shell thickness, whereas the Auger recombination time (a limiting aspect in technological applications when fast) slows down from 11 to 38 ps when increasing the shell thickness from 1.5 to 7MLs. Chemical and structural analyses evidence that InAs@ZnSe nanocrystals do not exhibit any strain at the core-shell interface, likely due to the formation of an InZnSe interlayer. This is supported by atomistic modeling, which indicates the interlayer as being composed of In, Zn, Se and cation vacancies, alike to the In2 ZnSe4 crystal structure. The simulations reveal an electronic structure consistent with that of type-I heterostructures, in which localized trap states can be passivated by a thick shell (>3ML) and excitons are confined in the core.
Collapse
Affiliation(s)
- Dongxu Zhu
- Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, Genova, 16163, Italy
| | - Houman Bahmani Jalali
- Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, Genova, 16163, Italy
- Photonic Nanomaterials, Istituto Italiano di Tecnologia, Via Morego 30, Genova, 16163, Italy
| | - Gabriele Saleh
- Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, Genova, 16163, Italy
| | - Francesco Di Stasio
- Photonic Nanomaterials, Istituto Italiano di Tecnologia, Via Morego 30, Genova, 16163, Italy
| | - Mirko Prato
- Materials Characterization, Istituto Italiano di Tecnologia, Via Morego 30, Genova, 16163, Italy
| | - Nefeli Polykarpou
- Inorganic Nanocrystals Laboratory, Department of Chemistry, University of Cyprus, Nicosia, 1678, Cyprus
| | - Andreas Othonos
- Laboratory of Ultrafast Science, Department of Physics, University of Cyprus, Nicosia, 1678, Cyprus
| | - Sotirios Christodoulou
- Inorganic Nanocrystals Laboratory, Department of Chemistry, University of Cyprus, Nicosia, 1678, Cyprus
| | - Yurii P Ivanov
- Electron Spectroscopy and Nanoscopy, Istituto Italiano di Tecnologia, Via Morego 30, Genova, 16163, Italy
| | - Giorgio Divitini
- Electron Spectroscopy and Nanoscopy, Istituto Italiano di Tecnologia, Via Morego 30, Genova, 16163, Italy
| | - Ivan Infante
- BCMaterials, Basque Center for Materials, Applications, and Nanostructures, UPV/EHU Science Park, Leioa, 48940, Spain
- Ikerbasque Basque Foundation for Science, Bilbao, 48009, Spain
| | - Luca De Trizio
- Chemistry Facility, Istituto Italiano di Tecnologia, Via Morego 30, Genova, 16163, Italy
| | - Liberato Manna
- Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, Genova, 16163, Italy
| |
Collapse
|
10
|
Lehner BU, Seidelmann T, Undeutsch G, Schimpf C, Manna S, Gawełczyk M, Covre da Silva SF, Yuan X, Stroj S, Reiter DE, Axt VM, Rastelli A. Beyond the Four-Level Model: Dark and Hot States in Quantum Dots Degrade Photonic Entanglement. NANO LETTERS 2023; 23:1409-1415. [PMID: 36745448 PMCID: PMC9951244 DOI: 10.1021/acs.nanolett.2c04734] [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: 12/02/2022] [Revised: 02/01/2023] [Indexed: 06/18/2023]
Abstract
Entangled photon pairs are essential for a multitude of quantum photonic applications. To date, the best performing solid-state quantum emitters of entangled photons are semiconductor quantum dots operated around liquid-helium temperatures. To favor the widespread deployment of these sources, it is important to explore and understand their behavior at temperatures accessible with compact Stirling coolers. Here we study the polarization entanglement among photon pairs from the biexciton-exciton cascade in GaAs quantum dots at temperatures up to ∼65 K. We observe entanglement degradation accompanied by changes in decay dynamics, which we ascribe to thermal population and depopulation of hot and dark states in addition to the four levels relevant for photon pair generation. Detailed calculations considering the presence and characteristics of the additional states and phonon-assisted transitions support the interpretation. We expect these results to guide the optimization of quantum dots as sources of highly entangled photons at elevated temperatures.
Collapse
Affiliation(s)
- Barbara Ursula Lehner
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Linz4040, Austria
- Secure
and Correct Systems Lab, Linz Institute
of Technology, 4040Linz, Austria
| | - Tim Seidelmann
- Theoretische
Physik III, Universität Bayreuth, 95440Bayreuth, Germany
| | - Gabriel Undeutsch
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Linz4040, Austria
| | - Christian Schimpf
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Linz4040, Austria
| | - Santanu Manna
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Linz4040, Austria
| | - Michał Gawełczyk
- Institute
of Theoretical Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, 50-370 Wrocław, Poland
| | | | - Xueyong Yuan
- School
of Physics, Southeast University, Nanjing211189, China
| | - Sandra Stroj
- Forschungszentrum
Mikrotechnik, FH Vorarlberg, 6850Dornbirn, Austria
| | - Doris E. Reiter
- Condensed
Matter Theory, TU Dortmund, 44221Dortmund, Germany
| | | | - Armando Rastelli
- Institute
of Semiconductor and Solid State Physics, Johannes Kepler University, Linz4040, Austria
| |
Collapse
|
11
|
Laferriére P, Haffouz S, Northeast DB, Poole PJ, Williams RL, Dalacu D. Position-Controlled Telecom Single Photon Emitters Operating at Elevated Temperatures. NANO LETTERS 2023; 23:962-968. [PMID: 36706023 PMCID: PMC9912373 DOI: 10.1021/acs.nanolett.2c04375] [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: 11/07/2022] [Revised: 01/25/2023] [Indexed: 06/18/2023]
Abstract
A key resource in quantum-secured communication protocols are single photon emitters. For long-haul optical networks, it is imperative to use photons at wavelengths compatible with telecom single mode fibers. We demonstrate high purity single photon emission at 1.31 μm using deterministically positioned InP photonic waveguide nanowires containing single InAsP quantum dot-in-a-rod structures. At excitation rates that saturate the emission, we obtain a single photon collection efficiency at first lens of 27.6% and a probability of multiphoton emission of g(2)(0) = 0.021. We have also evaluated the performance of the source as a function of temperature. Multiphoton emission probability increases with temperature with values of 0.11, 0.34, and 0.57 at 77, 220 and 300 K, respectively, which is attributed to an overlap of temperature-broadened excitonic emission lines. These results are a promising step toward scalably fabricating telecom single photon emitters that operate under relaxed cooling requirements.
Collapse
Affiliation(s)
- Patrick Laferriére
- National
Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6
- University
of Ottawa, Ottawa, Ontario, Canada K1N 6N5
| | - Sofiane Haffouz
- National
Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6
| | | | - Philip J. Poole
- National
Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6
| | - Robin L. Williams
- National
Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6
| | - Dan Dalacu
- National
Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6
- University
of Ottawa, Ottawa, Ontario, Canada K1N 6N5
| |
Collapse
|
12
|
Jun S, Choi M, Kim B, Morassi M, Tchernycheva M, Song HG, Yeo HS, Gogneau N, Cho YH. Enhancement of Single-Photon Purity and Coherence of III-Nitride Quantum Dot with Polarization-Controlled Quasi-Resonant Excitation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2205229. [PMID: 36449654 DOI: 10.1002/smll.202205229] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/18/2022] [Indexed: 06/17/2023]
Abstract
III-Nitride semiconductor-based quantum dots (QDs) play an essential role in solid-state quantum light sources because of their potential for room-temperature operation. However, undesired background emission from the surroundings deteriorates single-photon purity. Moreover, spectral diffusion causes inhomogeneous broadening and limits the applications of QDs in quantum photonic technologies. To overcome these obstacles, it is demonstrated that directly pumping carriers to the excited state of the QD reduces the number of carriers generated in the vicinities. The polarization-controlled quasi-resonant excitation is applied to InGaN QDs embedded in GaN nanowire. To analyze the different excitation mechanisms, polarization-resolved absorptions are investigated under the above-barrier bandgap, below-barrier bandgap, and quasi-resonant excitation conditions. By employing polarization-controlled quasi-resonant excitation, the linewidth is reduced from 353 to 272 µeV, and the second-order correlation value is improved from 0.470 to 0.231. Therefore, a greater single-photon purity can be obtained at higher temperatures due to decreased linewidth and background emission.
Collapse
Affiliation(s)
- Seongmoon Jun
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Minho Choi
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Baul Kim
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Martina Morassi
- Center for Nanosciences and Nanotechnologies, Paris-Saclay University, CNRS, UMR9001, Boulevard Thomas Gobert, Palaiseau, 91120, France
| | - Maria Tchernycheva
- Center for Nanosciences and Nanotechnologies, Paris-Saclay University, CNRS, UMR9001, Boulevard Thomas Gobert, Palaiseau, 91120, France
| | - Hyun Gyu Song
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Hwan-Seop Yeo
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Noëlle Gogneau
- Center for Nanosciences and Nanotechnologies, Paris-Saclay University, CNRS, UMR9001, Boulevard Thomas Gobert, Palaiseau, 91120, France
| | - Yong-Hoon Cho
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| |
Collapse
|
13
|
Bahmani Jalali H, De Trizio L, Manna L, Di Stasio F. Indium arsenide quantum dots: an alternative to lead-based infrared emitting nanomaterials. Chem Soc Rev 2022; 51:9861-9881. [PMID: 36408788 PMCID: PMC9743785 DOI: 10.1039/d2cs00490a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Indexed: 11/22/2022]
Abstract
Colloidal quantum dots (QDs) emitting in the infrared (IR) are promising building blocks for numerous photonic, optoelectronic and biomedical applications owing to their low-cost solution-processability and tunable emission. Among them, lead- and mercury-based QDs are currently the most developed materials. Yet, due to toxicity issues, the scientific community is focusing on safer alternatives. In this regard, indium arsenide (InAs) QDs are one of the best candidates as they can absorb and emit light in the whole near infrared spectral range and they are RoHS-compliant, with recent trends suggesting that there is a renewed interest in this class of materials. This review focuses on colloidal InAs QDs and aims to provide an up-to-date overview spanning from their synthesis and surface chemistry to post-synthesis modifications. We provide a comprehensive overview from initial synthetic methods to the most recent developments on the ability to control the size, size distribution, electronic properties and carrier dynamics. Then, we describe doping and alloying strategies applied to InAs QDs as well as InAs based heterostructures. Furthermore, we present the state-of-the-art applications of InAs QDs, with a particular focus on bioimaging and field effect transistors. Finally, we discuss open challenges and future perspectives.
Collapse
Affiliation(s)
- Houman Bahmani Jalali
- Photonic Nanomaterials, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
- Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Luca De Trizio
- Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Liberato Manna
- Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Francesco Di Stasio
- Photonic Nanomaterials, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy.
| |
Collapse
|
14
|
Fassi B, Driz S, Al-Douri Y, Ameri M, Abd El-Rehim A. Optical investigations of Cu2CdSnS 4 quaternary alloy nanostructure for indoor optical wireless communications. OPTICS COMMUNICATIONS 2022; 517:128351. [DOI: 10.1016/j.optcom.2022.128351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
|
15
|
Holewa P, Sakanas A, Gür UM, Mrowiński P, Huck A, Wang BY, Musiał A, Yvind K, Gregersen N, Syperek M, Semenova E. Bright Quantum Dot Single-Photon Emitters at Telecom Bands Heterogeneously Integrated on Si. ACS PHOTONICS 2022; 9:2273-2279. [PMID: 35880068 PMCID: PMC9306001 DOI: 10.1021/acsphotonics.2c00027] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Whereas the Si photonic platform is highly attractive for scalable optical quantum information processing, it lacks practical solutions for efficient photon generation. Self-assembled semiconductor quantum dots (QDs) efficiently emit photons in the telecom bands (1460-1625 nm) and allow for heterogeneous integration with Si. In this work, we report on a novel, robust, and industry-compatible approach for achieving single-photon emission from InAs/InP QDs heterogeneously integrated with a Si substrate. As a proof of concept, we demonstrate a simple vertical emitting device, employing a metallic mirror beneath the QD emitter, and experimentally obtained photon extraction efficiencies of ∼10%. Nevertheless, the figures of merit of our structures are comparable with values previously only achieved for QDs emitting at shorter wavelength or by applying technically demanding fabrication processes. Our architecture and the simple fabrication procedure allows for the demonstration of high-purity single-photon generation with a second-order correlation function at zero time delay, g (2)(τ = 0) < 0.02, without any corrections at continuous wave excitation at the liquid helium temperature and preserved up to 50 K. For pulsed excitation, we achieve the as-measured g (2)(0) down to 0.205 ± 0.020 (0.114 ± 0.020 with background coincidences subtracted).
Collapse
Affiliation(s)
- Paweł Holewa
- Laboratory
for Optical Spectroscopy of Nanostructures, Faculty of Fundamental
Problems of Technology, Department of Experimental Physics, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
- DTU
Fotonik, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Aurimas Sakanas
- DTU
Fotonik, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Ugur M. Gür
- DTU
Electrical Engineering, Technical University
of Denmark, Kongens Lyngby 2800, Denmark
| | - Paweł Mrowiński
- Laboratory
for Optical Spectroscopy of Nanostructures, Faculty of Fundamental
Problems of Technology, Department of Experimental Physics, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Alexander Huck
- Center
for Macroscopic Quantum States (bigQ), Department of Physics, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Bi-Ying Wang
- DTU
Fotonik, Technical University of Denmark, Kongens Lyngby 2800, Denmark
- Hefei
National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Anna Musiał
- Laboratory
for Optical Spectroscopy of Nanostructures, Faculty of Fundamental
Problems of Technology, Department of Experimental Physics, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Kresten Yvind
- DTU
Fotonik, Technical University of Denmark, Kongens Lyngby 2800, Denmark
- NanoPhoton-Center
for Nanophotonics, Technical University
of Denmark, Kongens Lyngby 2800, Denmark
| | - Niels Gregersen
- DTU
Fotonik, Technical University of Denmark, Kongens Lyngby 2800, Denmark
| | - Marcin Syperek
- Laboratory
for Optical Spectroscopy of Nanostructures, Faculty of Fundamental
Problems of Technology, Department of Experimental Physics, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Elizaveta Semenova
- DTU
Fotonik, Technical University of Denmark, Kongens Lyngby 2800, Denmark
- NanoPhoton-Center
for Nanophotonics, Technical University
of Denmark, Kongens Lyngby 2800, Denmark
| |
Collapse
|
16
|
Zielińska A, Musiał A, Wyborski P, Kuniej M, Heuser T, Srocka N, Grosse J, Reithmaier JP, Benyoucef M, Rodt S, Reitzenstein S, Rudno-Rudziński W. Temperature dependence of refractive indices of Al 0.9Ga 0.1As and In 0.53Al 0.1Ga 0.37As in the telecommunication spectral range. OPTICS EXPRESS 2022; 30:20225-20240. [PMID: 36224773 DOI: 10.1364/oe.457952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/05/2022] [Indexed: 06/16/2023]
Abstract
In this work, we determine the temperature dependence of refractive indices of In0.53Al0.1Ga0.37As and Al0.9Ga0.1As semiconductor alloys at telecommunication wavelengths in the range from room temperature down to 10 K. For that, we measure the temperature-dependent reflectance of two structures: with an Al0.9Ga0.1As/GaAs distributed Bragg reflector (DBR) designed for 1.3 µm and with an In0.53Al0.1Ga0.37As/InP DBR designed for 1.55 µm. The obtained experimental results are compared to DBR reflectivity spectra calculated within the transfer matrix method to determine refractive index values. We further show that changes due to the thermal expansion of the DBR layers are negligible for our method.
Collapse
|
17
|
Gajjela RSR, van Venrooij NRS, da Cruz AR, Skiba-Szymanska J, Stevenson RM, Shields AJ, Pryor CE, Koenraad PM. Study of Size, Shape, and Etch pit formation in InAs/InP Droplet Epitaxy Quantum Dots. NANOTECHNOLOGY 2022; 33:305705. [PMID: 35395644 DOI: 10.1088/1361-6528/ac659e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/07/2022] [Indexed: 06/14/2023]
Abstract
We investigated metal-organic vapor phase epitaxy grown droplet epitaxy (DE) and Stranski-Krastanov (SK) InAs/InP quantum dots (QDs) by cross-sectional scanning tunneling microscopy (X-STM). We present an atomic-scale comparison of structural characteristics of QDs grown by both growth methods proving that the DE yields more uniform and shape-symmetric QDs. Both DE and SKQDs are found to be truncated pyramid-shaped with a large and sharp top facet. We report the formation of localized etch pits for the first time in InAs/InP DEQDs with atomic resolution. We discuss the droplet etching mechanism in detail to understand the formation of etch pits underneath the DEQDs. A summary of the effect of etch pit size and position on fine structure splitting (FSS) is provided via thek·ptheory. Finite element (FE) simulations are performed to fit the experimental outward relaxation and lattice constant profiles of the cleaved QDs. The composition of QDs is estimated to be pure InAs obtained by combining both FE simulations and X-STM results. The preferential formation of {136} and {122} side facets was observed for the DEQDs. The formation of a DE wetting layer from As-P surface exchange is compared with the standard SKQDs wetting layer. The detailed structural characterization performed in this work provides valuable feedback for further growth optimization to obtain QDs with even lower FSS for applications in quantum technology.
Collapse
Affiliation(s)
- Raja S R Gajjela
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven 5612 AZ, The Netherlands
| | - Niels R S van Venrooij
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven 5612 AZ, The Netherlands
| | - Adonai R da Cruz
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven 5612 AZ, The Netherlands
| | - Joanna Skiba-Szymanska
- Toshiba Europe Limited, Cambridge Research Laboratory, 208 Science Park, Milton Road, Cambridge CB4 0GZ, United Kingdom
| | - R Mark Stevenson
- Toshiba Europe Limited, Cambridge Research Laboratory, 208 Science Park, Milton Road, Cambridge CB4 0GZ, United Kingdom
| | - Andrew J Shields
- Toshiba Europe Limited, Cambridge Research Laboratory, 208 Science Park, Milton Road, Cambridge CB4 0GZ, United Kingdom
| | - Craig E Pryor
- Department of Physics and Astronomy, Optical Science and Technology Center, University of Iowa, Iowa City, Iowa IA-52242, United States of America
| | - Paul M Koenraad
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven 5612 AZ, The Netherlands
| |
Collapse
|
18
|
Barbiero A, Huwer J, Skiba-Szymanska J, Müller T, Stevenson RM, Shields AJ. Design study for an efficient semiconductor quantum light source operating in the telecom C-band based on an electrically-driven circular Bragg grating. OPTICS EXPRESS 2022; 30:10919-10928. [PMID: 35473046 DOI: 10.1364/oe.452328] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
The development of efficient sources of single photons and entangled photon pairs emitting in the low-loss wavelength region around 1550 nm is crucial for long-distance quantum communication. Moreover, direct fiber coupling and electrical carrier injection are highly desirable for deployment in compact and user-friendly systems integrated with the existing fiber infrastructure. Here we present a detailed design study of circular Bragg gratings fabricated in InP slabs and operating in the telecom C-band. These devices enable the simultaneous enhancement of the X and XX spectral lines, with collection efficiency in numerical aperture 0.65 close to 90% for the wavelength range 1520 - 1580 nm and Purcell factor up to 15. We also investigate the coupling into a single mode fiber, which exceeds 70% in UHNA4. Finally, we propose a modified device design directly compatible with electrical carrier injection, reporting Purcell factors up to 20 and collection efficiency in numerical aperture 0.65 close to 70% for the whole telecom C-band.
Collapse
|
19
|
Sala EM, Godsland M, Na YI, Trapalis A, Heffernan J. Droplet epitaxy of InAs/InP quantum dots via MOVPE by using an InGaAs interlayer. NANOTECHNOLOGY 2021; 33:065601. [PMID: 34731846 DOI: 10.1088/1361-6528/ac3617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
InAs quantum dots (QDs) are grown on an In0.53Ga0.47As interlayer and embedded in an InP(100) matrix. They are fabricated via droplet epitaxy (DE) in a metal organic vapor phase epitaxy (MOVPE) reactor. Formation of metallic indium droplets on the In0.53Ga0.47As lattice-matched layer and their crystallization into QDs is demonstrated for the first time in MOVPE. The presence of the In0.53Ga0.47As layer prevents the formation of an unintentional non-stoichiometric 2D layer underneath and around the QDs, via suppression of the As-P exchange. The In0.53Ga0.47As layer affects the surface diffusion leading to a modified droplet crystallization process, where unexpectedly the size of the resulting QDs is found to be inversely proportional to the indium supply. Bright single dot emission is detected via micro-photoluminescence at low temperature, ranging from 1440 to 1600 nm, covering the technologically relevant telecom C-band. Transmission electron microscopy investigations reveal buried quantum dots with truncated pyramid shape without defects or dislocations.
Collapse
Affiliation(s)
- Elisa M Sala
- EPSRC National Epitaxy Facility, The University of Sheffield, North Campus, Broad Lane, S3 7HQ Sheffield, United Kingdom
- Department of Electronic and Electrical Engineering, The University of Sheffield, North Campus, Broad Lane, S37HQ Sheffield, United Kingdom
| | - Max Godsland
- Department of Electronic and Electrical Engineering, The University of Sheffield, North Campus, Broad Lane, S37HQ Sheffield, United Kingdom
| | - Young In Na
- Department of Electronic and Electrical Engineering, The University of Sheffield, North Campus, Broad Lane, S37HQ Sheffield, United Kingdom
| | - Aristotelis Trapalis
- EPSRC National Epitaxy Facility, The University of Sheffield, North Campus, Broad Lane, S3 7HQ Sheffield, United Kingdom
- Department of Electronic and Electrical Engineering, The University of Sheffield, North Campus, Broad Lane, S37HQ Sheffield, United Kingdom
| | - Jon Heffernan
- EPSRC National Epitaxy Facility, The University of Sheffield, North Campus, Broad Lane, S3 7HQ Sheffield, United Kingdom
- Department of Electronic and Electrical Engineering, The University of Sheffield, North Campus, Broad Lane, S37HQ Sheffield, United Kingdom
| |
Collapse
|
20
|
Smołka T, Posmyk K, Wasiluk M, Wyborski P, Gawełczyk M, Mrowiński P, Mikulicz M, Zielińska A, Reithmaier JP, Musiał A, Benyoucef M. Optical Quality of InAs/InP Quantum Dots on Distributed Bragg Reflector Emitting at 3rd Telecom Window Grown by Molecular Beam Epitaxy. MATERIALS (BASEL, SWITZERLAND) 2021; 14:6270. [PMID: 34771794 PMCID: PMC8585182 DOI: 10.3390/ma14216270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/09/2021] [Accepted: 10/18/2021] [Indexed: 11/23/2022]
Abstract
We present an experimental study on the optical quality of InAs/InP quantum dots (QDs). Investigated structures have application relevance due to emission in the 3rd telecommunication window. The nanostructures are grown by ripening-assisted molecular beam epitaxy. This leads to their unique properties, i.e., low spatial density and in-plane shape symmetry. These are advantageous for non-classical light generation for quantum technologies applications. As a measure of the internal quantum efficiency, the discrepancy between calculated and experimentally determined photon extraction efficiency is used. The investigated nanostructures exhibit close to ideal emission efficiency proving their high structural quality. The thermal stability of emission is investigated by means of microphotoluminescence. This allows to determine the maximal operation temperature of the device and reveal the main emission quenching channels. Emission quenching is predominantly caused by the transition of holes and electrons to higher QD's levels. Additionally, these carriers could further leave the confinement potential via the dense ladder of QD states. Single QD emission is observed up to temperatures of about 100 K, comparable to the best results obtained for epitaxial QDs in this spectral range. The fundamental limit for the emission rate is the excitation radiative lifetime, which spreads from below 0.5 to almost 1.9 ns (GHz operation) without any clear spectral dispersion. Furthermore, carrier dynamics is also determined using time-correlated single-photon counting.
Collapse
Affiliation(s)
- Tristan Smołka
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (T.S.); (K.P.); (M.W.); (P.W.); (P.M.); (M.M.); (A.Z.)
| | - Katarzyna Posmyk
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (T.S.); (K.P.); (M.W.); (P.W.); (P.M.); (M.M.); (A.Z.)
| | - Maja Wasiluk
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (T.S.); (K.P.); (M.W.); (P.W.); (P.M.); (M.M.); (A.Z.)
| | - Paweł Wyborski
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (T.S.); (K.P.); (M.W.); (P.W.); (P.M.); (M.M.); (A.Z.)
| | - Michał Gawełczyk
- Department of Theoretical Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland;
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, ul. Grudziądzka 5, 87-100 Toruń, Poland
| | - Paweł Mrowiński
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (T.S.); (K.P.); (M.W.); (P.W.); (P.M.); (M.M.); (A.Z.)
| | - Monika Mikulicz
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (T.S.); (K.P.); (M.W.); (P.W.); (P.M.); (M.M.); (A.Z.)
| | - Agata Zielińska
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (T.S.); (K.P.); (M.W.); (P.W.); (P.M.); (M.M.); (A.Z.)
| | - Johann Peter Reithmaier
- Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Institute of Nanostructure Technologies and Analytics (INA), University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany;
| | - Anna Musiał
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (T.S.); (K.P.); (M.W.); (P.W.); (P.M.); (M.M.); (A.Z.)
| | - Mohamed Benyoucef
- Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Institute of Nanostructure Technologies and Analytics (INA), University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany;
| |
Collapse
|
21
|
Kolatschek S, Nawrath C, Bauer S, Huang J, Fischer J, Sittig R, Jetter M, Portalupi SL, Michler P. Bright Purcell Enhanced Single-Photon Source in the Telecom O-Band Based on a Quantum Dot in a Circular Bragg Grating. NANO LETTERS 2021; 21:7740-7745. [PMID: 34478316 DOI: 10.1021/acs.nanolett.1c02647] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The combination of semiconductor quantum dots with photonic cavities is a promising way to realize nonclassical light sources with state-of-the-art performances regarding brightness, indistinguishability, and repetition rate. Here we demonstrate the coupling of InGaAs/GaAs QDs emitting in the telecom O-band to a circular Bragg grating cavity. We demonstrate a broadband geometric extraction efficiency enhancement by investigating two emission lines under above-band excitation, inside and detuned from the cavity mode, respectively. In the first case, a Purcell enhancement of 4 is attained. For the latter case, an end-to-end brightness of 1.4% with a brightness at the first lens of 23% is achieved. Using p-shell pumping, a combination of high count rate with pure single-photon emission (g(2)(0) = 0.01 in saturation) is achieved. Finally, a good single-photon purity (g(2)(0) = 0.13) together with a high detector count rate of 191 kcps is demonstrated for a temperature of up to 77 K.
Collapse
Affiliation(s)
- Sascha Kolatschek
- Institut für Halbleiteroptik und Funktionelle Grenzflächen (IHFG), Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Cornelius Nawrath
- Institut für Halbleiteroptik und Funktionelle Grenzflächen (IHFG), Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Stephanie Bauer
- Institut für Halbleiteroptik und Funktionelle Grenzflächen (IHFG), Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Jiasheng Huang
- Institut für Halbleiteroptik und Funktionelle Grenzflächen (IHFG), Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Julius Fischer
- Institut für Halbleiteroptik und Funktionelle Grenzflächen (IHFG), Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Robert Sittig
- Institut für Halbleiteroptik und Funktionelle Grenzflächen (IHFG), Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Michael Jetter
- Institut für Halbleiteroptik und Funktionelle Grenzflächen (IHFG), Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Simone Luca Portalupi
- Institut für Halbleiteroptik und Funktionelle Grenzflächen (IHFG), Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| | - Peter Michler
- Institut für Halbleiteroptik und Funktionelle Grenzflächen (IHFG), Center for Integrated Quantum Science and Technology (IQST) and SCoPE, University of Stuttgart, Allmandring 3, 70569 Stuttgart, Germany
| |
Collapse
|
22
|
Wroński PA, Wyborski P, Musiał A, Podemski P, Sęk G, Höfling S, Jabeen F. Metamorphic Buffer Layer Platform for 1550 nm Single-Photon Sources Grown by MBE on (100) GaAs Substrate. MATERIALS (BASEL, SWITZERLAND) 2021; 14:5221. [PMID: 34576444 PMCID: PMC8467047 DOI: 10.3390/ma14185221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/06/2021] [Accepted: 09/07/2021] [Indexed: 11/24/2022]
Abstract
We demonstrate single-photon emission with a low probability of multiphoton events of 5% in the C-band of telecommunication spectral range of standard silica fibers from molecular beam epitaxy grown (100)-GaAs-based structure with InAs quantum dots (QDs) on a metamorphic buffer layer. For this purpose, we propose and implement graded In content digitally alloyed InGaAs metamorphic buffer layer with maximal In content of 42% and GaAs/AlAs distributed Bragg reflector underneath to enhance the extraction efficiency of QD emission. The fundamental limit of the emission rate for the investigated structures is 0.5 GHz based on an emission lifetime of 1.95 ns determined from time-resolved photoluminescence. We prove the relevance of a proposed technology platform for the realization of non-classical light sources in the context of fiber-based quantum communication applications.
Collapse
Affiliation(s)
- Piotr Andrzej Wroński
- Technische Physik, University of Würzburg and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Am Hubland, D-97074 Würzburg, Germany; (S.H.); (F.J.)
| | - Paweł Wyborski
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.M.); (P.P.); (G.S.)
| | - Anna Musiał
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.M.); (P.P.); (G.S.)
| | - Paweł Podemski
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.M.); (P.P.); (G.S.)
| | - Grzegorz Sęk
- Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.M.); (P.P.); (G.S.)
| | - Sven Höfling
- Technische Physik, University of Würzburg and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Am Hubland, D-97074 Würzburg, Germany; (S.H.); (F.J.)
| | - Fauzia Jabeen
- Technische Physik, University of Würzburg and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Am Hubland, D-97074 Würzburg, Germany; (S.H.); (F.J.)
- Quantum Light and Matter Group, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton SO17 1BJ, UK
| |
Collapse
|
23
|
Zeuner KD, Jöns KD, Schweickert L, Reuterskiöld Hedlund C, Nuñez Lobato C, Lettner T, Wang K, Gyger S, Schöll E, Steinhauer S, Hammar M, Zwiller V. On-Demand Generation of Entangled Photon Pairs in the Telecom C-Band with InAs Quantum Dots. ACS PHOTONICS 2021; 8:2337-2344. [PMID: 34476289 PMCID: PMC8377713 DOI: 10.1021/acsphotonics.1c00504] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Indexed: 06/13/2023]
Abstract
Entangled photons are an integral part in quantum optics experiments and a key resource in quantum imaging, quantum communication, and photonic quantum information processing. Making this resource available on-demand has been an ongoing scientific challenge with enormous progress in recent years. Of particular interest is the potential to transmit quantum information over long distances, making photons the only reliable flying qubit. Entangled photons at the telecom C-band could be directly launched into single-mode optical fibers, enabling worldwide quantum communication via existing telecommunication infrastructure. However, the on-demand generation of entangled photons at this desired wavelength window has been elusive. Here, we show a photon pair generation efficiency of 69.9 ± 3.6% in the telecom C-band by an InAs/GaAs semiconductor quantum dot on a metamorphic buffer layer. Using a robust phonon-assisted two-photon excitation scheme we measure a maximum concurrence of 91.4 ± 3.8% and a peak fidelity to the Φ+ state of 95.2 ± 1.1%, verifying on-demand generation of strongly entangled photon pairs and marking an important milestone for interfacing quantum light sources with our classical fiber networks.
Collapse
Affiliation(s)
- Katharina D. Zeuner
- Department
of Applied Physics, Royal Institute of Technology,
Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| | - Klaus D. Jöns
- Department
of Applied Physics, Royal Institute of Technology,
Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| | - Lucas Schweickert
- Department
of Applied Physics, Royal Institute of Technology,
Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| | - Carl Reuterskiöld Hedlund
- Department
of Electrical Engineering, Royal Institute
of Technology, Electrum 229, 164 40 Kista, Sweden
| | - Carlos Nuñez Lobato
- Department
of Electrical Engineering, Royal Institute
of Technology, Electrum 229, 164 40 Kista, Sweden
| | - Thomas Lettner
- Department
of Applied Physics, Royal Institute of Technology,
Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| | - Kai Wang
- Department
of Applied Physics, Royal Institute of Technology,
Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| | - Samuel Gyger
- Department
of Applied Physics, Royal Institute of Technology,
Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| | - Eva Schöll
- Department
of Applied Physics, Royal Institute of Technology,
Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| | - Stephan Steinhauer
- Department
of Applied Physics, Royal Institute of Technology,
Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| | - Mattias Hammar
- Department
of Electrical Engineering, Royal Institute
of Technology, Electrum 229, 164 40 Kista, Sweden
| | - Val Zwiller
- Department
of Applied Physics, Royal Institute of Technology,
Albanova University Centre, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
| |
Collapse
|
24
|
Choi M, Jun S, Woo KY, Song HG, Yeo HS, Choi S, Park D, Park CH, Cho YH. Nanoscale Focus Pinspot for High-Purity Quantum Emitters via Focused-Ion-Beam-Induced Luminescence Quenching. ACS NANO 2021; 15:11317-11325. [PMID: 34165277 DOI: 10.1021/acsnano.1c00587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Epitaxially grown quantum dots (QDs), especially embedded in photonic structures, play an essential role in various quantum photonic systems as on-demand single-photon sources. However, these QDs often suffer from adjacent unwanted emitters, which contribute to the background noise of the QD emission and fundamentally limit the single-photon purity. In this paper, a nanoscale focus pinspot (NFP) technique using focused-ion-beam-induced luminescence quenching enables us to improve single-photon purity from site-controlled QD as a proof-of-concept experiment. The optical quality of the QD emission is not degraded while the signal-to-noise ratio of the QD is improved. Moreover, the QD after the NFP technique reveals the single-photon nature at further elevated temperatures owing to the reduced background noise. As the NFP technique is nondestructive, it retains the apparent physical structures and photonic functions, thereby indicating its promising potential for applying diverse high-purity quantum emitters, particularly integrated in photonic devices and circuits.
Collapse
Affiliation(s)
- Minho Choi
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Seongmoon Jun
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Kie Young Woo
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hyun Gyu Song
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hwan-Seop Yeo
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sunghan Choi
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Doyoun Park
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Chung-Hyun Park
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Yong-Hoon Cho
- Department of Physics and KI for the NanoCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea
| |
Collapse
|
25
|
Gajjela RSR, Hendriks AL, Douglas JO, Sala EM, Steindl P, Klenovský P, Bagot PAJ, Moody MP, Bimberg D, Koenraad PM. Structural and compositional analysis of (InGa)(AsSb)/GaAs/GaP Stranski-Krastanov quantum dots. LIGHT, SCIENCE & APPLICATIONS 2021; 10:125. [PMID: 34127643 PMCID: PMC8203795 DOI: 10.1038/s41377-021-00564-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 05/12/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
We investigated metal-organic vapor phase epitaxy grown (InGa)(AsSb)/GaAs/GaP Stranski-Krastanov quantum dots (QDs) with potential applications in QD-Flash memories by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography (APT). The combination of X-STM and APT is a very powerful approach to study semiconductor heterostructures with atomic resolution, which provides detailed structural and compositional information on the system. The rather small QDs are found to be of truncated pyramid shape with a very small top facet and occur in our sample with a very high density of ∼4 × 1011 cm-2. APT experiments revealed that the QDs are GaAs rich with smaller amounts of In and Sb. Finite element (FE) simulations are performed using structural data from X-STM to calculate the lattice constant and the outward relaxation of the cleaved surface. The composition of the QDs is estimated by combining the results from X-STM and the FE simulations, yielding ∼InxGa1 - xAs1 - ySby, where x = 0.25-0.30 and y = 0.10-0.15. Noticeably, the reported composition is in good agreement with the experimental results obtained by APT, previous optical, electrical, and theoretical analysis carried out on this material system. This confirms that the InGaSb and GaAs layers involved in the QD formation have strongly intermixed. A detailed analysis of the QD capping layer shows the segregation of Sb and In from the QD layer, where both APT and X-STM show that the Sb mainly resides outside the QDs proving that Sb has mainly acted as a surfactant during the dot formation. Our structural and compositional analysis provides a valuable insight into this novel QD system and a path for further growth optimization to improve the storage time of the QD-Flash memory devices.
Collapse
Affiliation(s)
- Raja S R Gajjela
- Department of Applied Physics, Eindhoven University of Technology, 5612 AZ, Eindhoven, The Netherlands.
| | - Arthur L Hendriks
- Department of Applied Physics, Eindhoven University of Technology, 5612 AZ, Eindhoven, The Netherlands
| | - James O Douglas
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
| | - Elisa M Sala
- Center for Nanophotonics, Institute for Solid State Physics, TechnischeUniversität Berlin, Hardenbergstr. 36, 10623, Berlin, Germany
- EPSRC National Epitaxy Facility, The University of Sheffield, North Campus, Broad Lane, Sheffield, S3 7HQ, UK
| | - Petr Steindl
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská267/2, 61137, Brno, Czech Republic
- Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504 2300 RA, Leiden, Netherlands
| | - Petr Klenovský
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská267/2, 61137, Brno, Czech Republic
- Czech Metrology Institute, Okružní 31, 63800, Brno, Czech Republic
| | - Paul A J Bagot
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
| | - Michael P Moody
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
| | - Dieter Bimberg
- Center for Nanophotonics, Institute for Solid State Physics, TechnischeUniversität Berlin, Hardenbergstr. 36, 10623, Berlin, Germany
- "Bimberg Chinese-German Center for Green Photonics" Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences at CIOMP, 13033, Changchun, China
| | - Paul M Koenraad
- Department of Applied Physics, Eindhoven University of Technology, 5612 AZ, Eindhoven, The Netherlands
| |
Collapse
|
26
|
Moshiri SMM, Nozhat N. Smart optical cross dipole nanoantenna with multibeam pattern. Sci Rep 2021; 11:5047. [PMID: 33658603 PMCID: PMC7930033 DOI: 10.1038/s41598-021-84495-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 02/17/2021] [Indexed: 11/09/2022] Open
Abstract
In this paper, an optical smart multibeam cross dipole nano-antenna has been proposed by combining the absorption characteristic of graphene and applying different arrangements of directors. By introducing a cross dipole nano-antenna with two V-shaped coupled elements, the maximum directivity of 8.79 dBi has been obtained for unidirectional radiation pattern. Also, by applying various arrangements of circular sectors as director, different types of radiation pattern such as bi- and quad-directional have been attained with directivities of 8.63 and 8.42 dBi, respectively, at the wavelength of 1550 nm. The maximum absorption power of graphene can be tuned by choosing an appropriate chemical potential. Therefore, the radiation beam of the proposed multibeam cross dipole nano-antenna has been controlled dynamically by applying a monolayer graphene. By choosing a suitable chemical potential of graphene for each arm of the suggested cross dipole nano-antenna without the director, the unidirectional radiation pattern shifts ± 13° at the wavelength of 1550 nm. Also, for the multibeam nano-antenna with different arrangements of directors, the bi- and quad-directional radiation patterns have been smartly modified to uni- and bi-directional ones with the directivities of 10.1 and 9.54 dBi, respectively. It is because of the graphene performance as an absorptive or transparent element for different chemical potentials. This feature helps us to create a multipath wireless link with the capability to control the accessibility of each receiver.
Collapse
Affiliation(s)
| | - Najmeh Nozhat
- Department of Electrical Engineering, Shiraz University of Technology, 7155713876, Shiraz, Iran.
| |
Collapse
|
27
|
Wyborski P, Musiał A, Mrowiński P, Podemski P, Baumann V, Wroński P, Jabeen F, Höfling S, Sęk G. InP-Substrate-Based Quantum Dashes on a DBR as Single-Photon Emitters at the Third Telecommunication Window. MATERIALS (BASEL, SWITZERLAND) 2021; 14:759. [PMID: 33562831 PMCID: PMC7915660 DOI: 10.3390/ma14040759] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 01/30/2021] [Accepted: 02/01/2021] [Indexed: 11/16/2022]
Abstract
We investigated emission properties of photonic structures with InAs/InGaAlAs/InP quantum dashes grown by molecular beam epitaxy on a distributed Bragg reflector. In high-spatial-resolution photoluminescence experiment, well-resolved sharp spectral lines are observed and single-photon emission is detected in the third telecommunication window characterized by very low multiphoton events probabilities. The photoluminescence spectra measured on simple photonic structures in the form of cylindrical mesas reveal significant intensity enhancement by a factor of 4 when compared to a planar sample. These results are supported by simulations of the electromagnetic field distribution, which show emission extraction efficiencies even above 18% for optimized designs. When combined with relatively simple and undemanding fabrication approach, it makes this kind of structures competitive with the existing solutions in that spectral range and prospective in the context of efficient and practical single-photon sources for fiber-based quantum networks applications.
Collapse
Affiliation(s)
- Paweł Wyborski
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.M.); (P.M.); (P.P.); (G.S.)
| | - Anna Musiał
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.M.); (P.M.); (P.P.); (G.S.)
| | - Paweł Mrowiński
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.M.); (P.M.); (P.P.); (G.S.)
| | - Paweł Podemski
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.M.); (P.M.); (P.P.); (G.S.)
| | - Vasilij Baumann
- Technische Physik, University of Würzburg and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Am Hubland, D-97074 Würzburg, Germany; (V.B.); (P.W.); (F.J.); (S.H.)
| | - Piotr Wroński
- Technische Physik, University of Würzburg and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Am Hubland, D-97074 Würzburg, Germany; (V.B.); (P.W.); (F.J.); (S.H.)
| | - Fauzia Jabeen
- Technische Physik, University of Würzburg and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Am Hubland, D-97074 Würzburg, Germany; (V.B.); (P.W.); (F.J.); (S.H.)
- Faculty of Engineering and Physical Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Sven Höfling
- Technische Physik, University of Würzburg and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, Am Hubland, D-97074 Würzburg, Germany; (V.B.); (P.W.); (F.J.); (S.H.)
- School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, UK
| | - Grzegorz Sęk
- Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland; (A.M.); (P.M.); (P.P.); (G.S.)
| |
Collapse
|
28
|
Lee CM, Buyukkaya MA, Harper S, Aghaeimeibodi S, Richardson CJK, Waks E. Bright Telecom-Wavelength Single Photons Based on a Tapered Nanobeam. NANO LETTERS 2021; 21:323-329. [PMID: 33338376 DOI: 10.1021/acs.nanolett.0c03680] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Telecom-wavelength single photons are essential components for long-distance quantum networks. However, bright and pure single photon sources at telecom wavelengths remain challenging to achieve. Here, we demonstrate a bright telecom-wavelength single photon source based on a tapered nanobeam containing InAs/InP quantum dots. The tapered nanobeam enables directional and Gaussian-like far-field emission of the quantum dots. As a result, using above-band excitation we obtain an end-to-end brightness of 4.1 ± 0.1% and first-lens brightness of 27.0 ± 0.1% at the ∼1300 nm wavelength. Furthermore, we adopt quasi-resonant excitation to reduce both multiphoton emission and decoherence from unwanted charge carriers. As a result, we achieve a coherence time of 523 ± 16 ps and postselected Hong-Ou-Mandel visibility of 0.91 ± 0.09 along with a comparable first-lens brightness of 21.0 ± 0.1%. These results represent a major step toward a practical fiber-based single photon source at telecom wavelengths for long-distance quantum networks.
Collapse
Affiliation(s)
- Chang-Min Lee
- Department of Electrical and Computer Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, United States
| | - Mustafa Atabey Buyukkaya
- Department of Electrical and Computer Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, United States
| | - Samuel Harper
- Department of Electrical and Computer Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, United States
| | - Shahriar Aghaeimeibodi
- Department of Electrical and Computer Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, United States
| | | | - Edo Waks
- Department of Electrical and Computer Engineering and Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, United States
- Joint Quantum Institute, University of Maryland and the National Institute of Standards and Technology, College Park, Maryland 20742, United States
| |
Collapse
|
29
|
Gajjela RSR, Koenraad PM. Atomic-Scale Characterization of Droplet Epitaxy Quantum Dots. NANOMATERIALS 2021; 11:nano11010085. [PMID: 33401568 PMCID: PMC7823520 DOI: 10.3390/nano11010085] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 12/21/2020] [Accepted: 12/29/2020] [Indexed: 01/30/2023]
Abstract
The fundamental understanding of quantum dot (QD) growth mechanism is essential to improve QD based optoelectronic devices. The size, shape, composition, and density of the QDs strongly influence the optoelectronic properties of the QDs. In this article, we present a detailed review on atomic-scale characterization of droplet epitaxy quantum dots by cross-sectional scanning tunneling microscopy (X-STM) and atom probe tomography (APT). We will discuss both strain-free GaAs/AlGaAs QDs and strained InAs/InP QDs grown by droplet epitaxy. The effects of various growth conditions on morphology and composition are presented. The efficiency of methods such as flushing technique is shown by comparing with conventional droplet epitaxy QDs to further gain control over QD height. A detailed characterization of etch pits in both QD systems is provided by X-STM and APT. This review presents an overview of detailed structural and compositional analysis that have assisted in improving the fabrication of QD based optoelectronic devices grown by droplet epitaxy.
Collapse
|
30
|
Shooter G, Xiang ZH, Müller JRA, Skiba-Szymanska J, Huwer J, Griffiths J, Mitchell T, Anderson M, Müller T, Krysa AB, Mark Stevenson R, Heffernan J, Ritchie DA, Shields AJ. 1GHz clocked distribution of electrically generated entangled photon pairs. OPTICS EXPRESS 2020; 28:36838-36848. [PMID: 33379768 DOI: 10.1364/oe.405466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/31/2020] [Indexed: 06/12/2023]
Abstract
Quantum networks are essential for realising distributed quantum computation and quantum communication. Entangled photons are a key resource, with applications such as quantum key distribution, quantum relays, and quantum repeaters. All components integrated in a quantum network must be synchronised and therefore comply with a certain clock frequency. In quantum key distribution, the most mature technology, clock rates have reached and exceeded 1GHz. Here we show the first electrically pulsed sub-Poissonian entangled photon source compatible with existing fiber networks operating at this clock rate. The entangled LED is based on InAs/InP quantum dots emitting in the main telecom window, with a multi-photon probability of less than 10% per emission cycle and a maximum entanglement fidelity of 89%. We use this device to demonstrate GHz clocked distribution of entangled qubits over an installed fiber network between two points 4.6km apart.
Collapse
|
31
|
Akamatsu T, Tomioka K, Motohisa J. Demonstration of InP/InAsP/InP axial heterostructure nanowire array vertical LEDs. NANOTECHNOLOGY 2020; 31:394003. [PMID: 32658871 DOI: 10.1088/1361-6528/ab9bd2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Semiconductor nanowires (NWs), which have nanoscale footprints, enable us to realize various quantum structures with excellent position and size controllability, utilizing a wide range of materials for heterostructures. In addition, enhancing light extraction and controlling spontaneous emission by modifying their size and shape are possible. Thus, NWs are promising materials for nanoscale light sources applicable from visible to telecommunication bands. In this study, we grew InP/InAsP/InP axial heterostructure NWs, where the InAsP layer was embedded to serve as an active layer, by selective-area growth and demonstrated vertical NW array light-emitting diodes (LEDs) as a step towards realizing on-demand single photon sources. The NW array LEDs showed rectifying characteristics and electroluminescence originating from the embedded InAsP layer in the near-infrared region.
Collapse
Affiliation(s)
- Tomoya Akamatsu
- Graduate School of Information Science and Technology and Research Center for Integrated Quantum Electronics, Hokkaido University, North 14 West 9, Sapporo 060-0814, Japan
| | | | | |
Collapse
|
32
|
Yang J, Nawrath C, Keil R, Joos R, Zhang X, Höfer B, Chen Y, Zopf M, Jetter M, Luca Portalupi S, Ding F, Michler P, Schmidt OG. Quantum dot-based broadband optical antenna for efficient extraction of single photons in the telecom O-band. OPTICS EXPRESS 2020; 28:19457-19468. [PMID: 32672222 DOI: 10.1364/oe.395367] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/24/2020] [Indexed: 06/11/2023]
Abstract
Long-distance fiber-based quantum communication relies on efficient non-classical light sources operating at telecommunication wavelengths. Semiconductor quantum dots are promising candidates for on-demand generation of single photons and entangled photon pairs for such applications. However, their brightness is strongly limited due to total internal reflection at the semiconductor/vacuum interface. Here we overcome this limitation using a dielectric antenna structure. The non-classical light source consists of a gallium phosphide solid immersion lens in combination with a quantum dot nanomembrane emitting single photons in the telecom O-band. With this device, the photon extraction is strongly increased in a broad spectral range. A brightness of 17% (numerical aperture of 0.6) is obtained experimentally, with a single photon purity of g(2)(0)=0.049±0.02 at saturation power. This brings the practical implementation of quantum communication networks one step closer.
Collapse
|
33
|
Zhao TM, Chen Y, Yu Y, Li Q, Davanco M, Liu J. Advanced technologies for quantum photonic devices based on epitaxial quantum dots. ADVANCED QUANTUM TECHNOLOGIES 2020; 3:10.1002/qute.201900034. [PMID: 36452403 PMCID: PMC9706462 DOI: 10.1002/qute.201900034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Indexed: 05/12/2023]
Abstract
Quantum photonic devices are candidates for realizing practical quantum computers and networks. The development of integrated quantum photonic devices can greatly benefit from the ability to incorporate different types of materials with complementary, superior optical or electrical properties on a single chip. Semiconductor quantum dots (QDs) serve as a core element in the emerging modern photonic quantum technologies by allowing on-demand generation of single-photons and entangled photon pairs. During each excitation cycle, there is one and only one emitted photon or photon pair. QD photonic devices are on the verge of unfolding for advanced quantum technology applications. In this review, we focus on the latest significant progress of QD photonic devices. We first discuss advanced technologies in QD growth, with special attention to droplet epitaxy and site-controlled QDs. Then we overview the wavelength engineering of QDs via strain tuning and quantum frequency conversion techniques. We extend our discussion to advanced optical excitation techniques recently developed for achieving the desired emission properties of QDs. Finally, the advances in heterogeneous integration of active quantum light-emitting devices and passive integrated photonic circuits are reviewed, in the context of realizing scalable quantum information processing chips.
Collapse
Affiliation(s)
- Tian Ming Zhao
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Yan Chen
- Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Ying Yu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Qing Li
- Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Marcelo Davanco
- Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Jin Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| |
Collapse
|
34
|
Gurioli M, Wang Z, Rastelli A, Kuroda T, Sanguinetti S. Droplet epitaxy of semiconductor nanostructures for quantum photonic devices. NATURE MATERIALS 2019; 18:799-810. [PMID: 31086322 DOI: 10.1038/s41563-019-0355-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Accepted: 03/22/2019] [Indexed: 05/25/2023]
Abstract
The long dreamed 'quantum internet' would consist of a network of quantum nodes (solid-state or atomic systems) linked by flying qubits, naturally based on photons, travelling over long distances at the speed of light, with negligible decoherence. A key component is a light source, able to provide single or entangled photon pairs. Among the different platforms, semiconductor quantum dots (QDs) are very attractive, as they can be integrated with other photonic and electronic components in miniaturized chips. In the early 1990s two approaches were developed to synthetize self-assembled epitaxial semiconductor QDs, or 'artificial atoms'-namely, the Stranski-Krastanov (SK) and the droplet epitaxy (DE) methods. Because of its robustness and simplicity, the SK method became the workhorse to achieve several breakthroughs in both fundamental and technological areas. The need for specific emission wavelengths or structural and optical properties has nevertheless motivated further research on the DE method and its more recent development, local droplet etching (LDE), as complementary routes to obtain high-quality semiconductor nanostructures. The recent reports on the generation of highly entangled photon pairs, combined with good photon indistinguishability, suggest that DE and LDE QDs may complement (and sometimes even outperform) conventional SK InGaAs QDs as quantum emitters. We present here a critical survey of the state of the art of DE and LDE, highlighting the advantages and weaknesses, the achievements and challenges that are still open, in view of applications in quantum communication and technology.
Collapse
Affiliation(s)
| | - Zhiming Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, China
| | | | | | | |
Collapse
|
35
|
Gyger S, Zeuner KD, Jöns KD, Elshaari AW, Paul M, Popov S, Hedlund CR, Hammar M, Ozolins O, Zwiller V. Reconfigurable frequency coding of triggered single photons in the telecom C-band. OPTICS EXPRESS 2019; 27:14400-14406. [PMID: 31163890 DOI: 10.1364/oe.27.014400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 04/19/2019] [Indexed: 06/09/2023]
Abstract
In this work, we demonstrate reconfigurable frequency manipulation of quantum states of light in the telecom C-band. Triggered single photons are encoded in a superposition state of three channels using sidebands up to 53 GHz created by an off-the-shelf phase modulator. The single photons are emitted by an InAs/GaAs quantum dot grown by metal-organic vapor-phase epitaxy within the transparency window of the backbone fiber optical network. A cross-correlation measurement of the sidebands demonstrates the preservation of the single photon nature; an important prerequisite for future quantum technology applications using the existing telecommunication fiber network.
Collapse
|
36
|
Zwolak JP, Kalantre SS, Wu X, Ragole S, Taylor JM. QFlow lite dataset: A machine-learning approach to the charge states in quantum dot experiments. PLoS One 2018; 13:e0205844. [PMID: 30332463 PMCID: PMC6192646 DOI: 10.1371/journal.pone.0205844] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 09/25/2018] [Indexed: 11/18/2022] Open
Abstract
Background Over the past decade, machine learning techniques have revolutionized how research and science are done, from designing new materials and predicting their properties to data mining and analysis to assisting drug discovery to advancing cybersecurity. Recently, we added to this list by showing how a machine learning algorithm (a so-called learner) combined with an optimization routine can assist experimental efforts in the realm of tuning semiconductor quantum dot (QD) devices. Among other applications, semiconductor quantum dots are a candidate system for building quantum computers. In order to employ QDs, one needs to tune the devices into a desirable configuration suitable for quantum computing. While current experiments adjust the control parameters heuristically, such an approach does not scale with the increasing size of the quantum dot arrays required for even near-term quantum computing demonstrations. Establishing a reliable protocol for tuning QD devices that does not rely on the gross-scale heuristics developed by experimentalists is thus of great importance. Materials and methods To implement the machine learning-based approach, we constructed a dataset of simulated QD device characteristics, such as the conductance and the charge sensor response versus the applied electrostatic gate voltages. The gate voltages are the experimental ‘knobs’ for tuning the device into useful regimes. Here, we describe the methodology for generating the dataset, as well as its validation in training convolutional neural networks. Results and discussion From 200 training sets sampled randomly from the full dataset, we show that the learner’s accuracy in recognizing the state of a device is ≈ 96.5% when using either current-based or charge-sensor-based training. The spread in accuracy over our 200 training sets is 0.5% and 1.8% for current- and charge-sensor-based data, respectively. In addition, we also introduce a tool that enables other researchers to use this approach for further research: QFlow lite—a Python-based mini-software suite that uses the dataset to train neural networks to recognize the state of a device and differentiate between states in experimental data. This work gives the definitive reference for the new dataset that will help enable researchers to use it in their experiments or to develop new machine learning approaches and concepts.
Collapse
Affiliation(s)
- Justyna P. Zwolak
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, 20742, United States of America
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States of America
- * E-mail:
| | - Sandesh S. Kalantre
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, 20742, United States of America
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States of America
- Department of Physics, Indian Institute of Technology - Bombay, Mumbai, 400076, India
| | - Xingyao Wu
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, 20742, United States of America
- Joint Quantum Institute, University of Maryland, College Park, MD, 20742, United States of America
| | - Stephen Ragole
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, 20742, United States of America
- Joint Quantum Institute, University of Maryland, College Park, MD, 20742, United States of America
| | - Jacob M. Taylor
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD, 20742, United States of America
- National Institute of Standards and Technology, Gaithersburg, MD, 20899, United States of America
- Joint Quantum Institute, University of Maryland, College Park, MD, 20742, United States of America
| |
Collapse
|
37
|
Müller T, Skiba-Szymanska J, Krysa AB, Huwer J, Felle M, Anderson M, Stevenson RM, Heffernan J, Ritchie DA, Shields AJ. A quantum light-emitting diode for the standard telecom window around 1,550 nm. Nat Commun 2018; 9:862. [PMID: 29491362 PMCID: PMC5830408 DOI: 10.1038/s41467-018-03251-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 01/29/2018] [Indexed: 11/23/2022] Open
Abstract
Single photons and entangled photon pairs are a key resource of many quantum secure communication and quantum computation protocols, and non-Poissonian sources emitting in the low-loss wavelength region around 1,550 nm are essential for the development of fibre-based quantum network infrastructure. However, reaching this wavelength window has been challenging for semiconductor-based quantum light sources. Here we show that quantum dot devices based on indium phosphide are capable of electrically injected single photon emission in this wavelength region. Using the biexciton cascade mechanism, they also produce entangled photons with a fidelity of 87 ± 4%, sufficient for the application of one-way error correction protocols. The material system further allows for entangled photon generation up to an operating temperature of 93 K. Our quantum photon source can be directly integrated with existing long distance quantum communication and cryptography systems, and provides a promising material platform for developing future quantum network hardware.
Collapse
Affiliation(s)
- T Müller
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK.
| | - J Skiba-Szymanska
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK
| | - A B Krysa
- EPSRC National Epitaxy Facility, University of Sheffield, Sheffield, S1 3JD, UK
| | - J Huwer
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK
| | - M Felle
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK
- Engineering Department, Cambridge University, 9 J J Thomson Avenue, Cambridge, CB3 0FA, UK
| | - M Anderson
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK
- Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - R M Stevenson
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK
| | - J Heffernan
- Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, S1 3JD, UK
| | - D A Ritchie
- Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, UK
| | - A J Shields
- Toshiba Research Europe Limited, 208 Science Park, Milton Road, Cambridge, CB4 0GZ, UK
| |
Collapse
|