Prof. Pawel Hawrylak Profile

Prof. Pawel Hawrylak

at University of Ottawa

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Publications (8)

Proceedings Article | 24 February 2020 Presentation + Paper

Room-temperature multi-phonon upconversion photoluminescence in monolayer semiconductor WS2

J. Jadczak, L. Bryja, J. Kutrowska-Girzycka, P. Kapuściński, M. Bieniek, Y. S. Huang, P. Hawrylak

Proceedings Volume 11298, 112980K (2020) https://doi.org/10.1117/12.2554270

KEYWORDS: Upconversion, Excitons, Luminescence, Phonons, Semiconductors, Temperature metrology, Absorption, Physics, Solids, Dielectrics

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Proceedings Article | 29 May 2013 Paper

Graphene-based integrated electronic, photonic and spintronic circuit

P. Potasz, A. Güçlü, I. Ozfidan, M. Korkusinski, P. Hawrylak

Proceedings Volume 8725, 87250G (2013) https://doi.org/10.1117/12.2016607

KEYWORDS: Graphene, Magnetism, Quantum dots, Chemical species, Spintronics, Magnetic semiconductors, Semiconductors, Photons, Nanostructures, Photonic integrated circuits

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Proceedings Article | 23 January 2010 Paper

Scalable routes to single and entangled photon pair sources: tailored InAs/InP quantum dots in photonic crystal microcavities

Dan Dalacu, Khaled Mnaymneh, Vera Sazonova, Philip Poole, Geof Aers, Ross Cheriton, Mike Reimer, Jean Lapointe, Pawel Hawrylak, Marek Korkusiński, Eugene Kadantsev, Robin Williams

Proceedings Volume 7608, 76082G (2010) https://doi.org/10.1117/12.846729

KEYWORDS: Quantum dots, Photonic crystals, Oxides, Silica, Optical microcavities, Semiconductors, Process control, Control systems, Oxidation, Directed self assembly

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Proceedings Article | 14 June 2004 Paper

Dephasing processes in InGaAs quantum dots and quantum-dot molecules

Paola Borri, Wolfgang Langbein, S. Schneider, Ulrike Woggon, Markus Schwab, Manfred Bayer, Roman Sellin, Dongxun Ouyang, Dieter Bimberg, S. Fafard, Zbigniew Wasilewski, Pawel Hawrylak

Proceedings Volume 5361, (2004) https://doi.org/10.1117/12.531544

KEYWORDS: Excitons, Quantum dots, Phonons, Molecules, Signal detection, Indium gallium arsenide, Picosecond phenomena, Temperature metrology, Polarization, Acoustics

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Proceedings Article | 11 June 2003 Paper

Entangled exciton states in quantum dot molecules

M. Bayer, G. Ortner, A. Larionov, A. Kress, Alfred Forchel, Pawel Hawrylak, K. Hinzer, M. Korkusinski, Simon Fafard, Zbigniew Wasilewski, Thomas Reinecke, Yu. Lyanda-Geller

Proceedings Volume 5023, (2003) https://doi.org/10.1117/12.514621

KEYWORDS: Quantum dots, Molecules, Excitons, Gallium arsenide, Particles, Chemical species, Quantum communications, Quantum optics, Quantum information, Quantum computing

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Currently there is strong interest in realizing implementations of quantum computation and quantum cryptography in a solid state environment. One of the systems that are actively studied are semiconductor quantum dots (QDs). Due to their discrete energy level structure, they are often called artificial atoms, and they attract immediately interest of quantum information science since they allow to mimic the design developed for atomic physics systems such as ions in traps or atoms in cavities. However, despite of the similarities, one has to keep in main that any elementary excitation in a QD has a generic many-body character. An essential building block of a quantum processor is a quantum gate which entangles the states of two quantum bits. Recently it has been proposed that a pair of vertically aligned QDs could be used as an optically driven quantum gate: The quantum bits are individual carriers either on dot zero or dot one. The different dot indices play the same role as a "spin," therefore we term them "isospin." Quantum mechanical tunneling between the dots rotates the "isospin" and leads to superposition of two quantum dot states. The quantum gate is built when two different particles, an electron and a hole, are created optically. The two particles form entangled isospin states. The entanglement can be controlled by application of an electric field along the heterostructure growth direction. Here we present spectroscopic studies on single quantum dot molecules (QDMs) with different vertical separation between the dots that support the feasibility of this proposal. The comparison of the evolution of the excitonic recombination spectrum with the results of calculations allows us to demonstrate coherent tunneling of electrons and holes across the separating barrier and the formation of entangled exciton states. For a given barrier width, we find only small variations of the tunneling induced splitting between the entangled states demonstrating a good homogeneity within the obtained QDM ensembles.

Proceedings Article | 15 December 2000 Paper

Single-dot spectroscopy of multiexcitons in AlInAs/AlGaAs quantum dots

Karin Hinzer, M. Bayer, O. Stern, A. Gorbunov, Alfred Forchel, Pawel Hawrylak, Jean Lapointe, Simon Fafard

Proceedings Volume 4087, (2000) https://doi.org/10.1117/12.406453

KEYWORDS: Excitons, Magnetism, Luminescence, Spectroscopy, Quantum dots, Chemical species, Indium arsenide, Gallium arsenide, Quantum communications, Nanostructures

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Proceedings Article | 11 July 2000 Paper

Quantum dot devices

Simon Fafard, Hui Liu, Zbigniew Wasilewski, John McCaffrey, M. Spanner, Sylvain Raymond, C. Allen, Karin Hinzer, Jean Lapointe, C. Struby, Ming Gao, Pawel Hawrylak, C. Gould, A. Sachrajda, P. Zawadzki

Proceedings Volume 4078, (2000) https://doi.org/10.1117/12.392130

KEYWORDS: Quantum dots, Spectroscopy, Gallium arsenide, Semiconductor lasers, Indium arsenide, Transmission electron microscopy, Optical storage, Luminescence, Electrons, Quantum wells

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From a recent study of the growth and optical properties of quantum dots (QD's), we demonstrated that artificial atoms with sharp electronic shells can be fabricated with good control, using self-assembled QD's grown by molecular beam epitaxy. Size and shape engineering of the QD's during growth permits the tailoring of their intersublevel energy spacings. We demonstrate a much improved uniformity of the macroscopic ensembles of QD's, with well-resolved electronic shells. In addition to size and shape engineering of the QDS's in the case of single-layer samples, we demonstrate significant improvements in the uniformity of the vertically self-aligned stacked QD's. State-filling spectroscopy of the zero-dimensional transitions between confined electrons and holes demonstrates that the energy levels are readily tunable. One to five confined levels, with an inter-level energy spacing between 25 and 90 meV, are obtained by adjusting the growth temperature or with post-growth annealings. Such QD's having well-defined excited-states have been grown in the active region of devices and results will be presented for lasers, detectors, or for structures displaying optical memory effects. For example, QD laser diodes with well-defined electronic shells are fabricated, and shape-engineered stacks of self-aligned QD's are used to increase the gain in the active region. Lasing is observed in the upper QD shells for small gain media, and progresses towards the QD ground states for longer cavity lengths. We obtained at 77K thresholds for J_th=15 A/cm² for a 2 mm cavity lasing in the first excited state (p-shell), and at 300K for a 5 mm cavity, J_th is ~430A/cm² with lasing in the d-shell. For an increased QD density, J_th is smaller than 100A/cm² at room temperature. For inter- sublevel transitions, we demonstrated broadband normal incidence detection with responsivity approaching 1A/W at a detection wavelength of 5 microns. For interband detection, the photoluminescence decay time of p-i-n diode can be changed from ~3nsec to ~0.3nsec (3Ghz) with a reverse bias. For Qds capped with less than ~10 nm, remarkable charge transfers between QD and surface states lead to optical memory effects lasting over time-scales of several minutes.

Proceedings Article | 1 October 1990 Paper

Influences of resonantly accumulated free electrons on optical absorption and emission in biased double-barrier resonant tunnelling structures

N. Sylvain Charbonneau, Jeffrey Young, Pawel Hawrylak, Anthony SpringThorpe

Proceedings Volume 1283, (1990) https://doi.org/10.1117/12.20756

KEYWORDS: Absorption, Electrons, Excitons, Quantum wells, Luminescence, Physics, Superlattices, Optical properties, Gallium arsenide, Dye lasers

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