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Pablo Bianucci

Concordia University (Canada), Physics, Faculty Member

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University of St Andrews

School of the Art Institute of Chicago

Harvey E Crichton

University of Oxford

Arizona State University

Estela Blaisten-Barojas

George Mason University

Queen Mary, University of London

Leopoldo Martín

Technion Israel Institute of Technology

University of Malta

University of Dr moulay taher

University of Regensburg

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Papers by Pablo Bianucci

Mode structure in the luminescence of Si-nc in cylindrical microcavities

Physica E-low-dimensional Systems & Nanostructures, 2009

We present photoluminescence studies of silicon-nanocrystal (Si-nc)-coated cylindrical microcavit... more We present photoluminescence studies of silicon-nanocrystal (Si-nc)-coated cylindrical microcavities. The particular geometries investigated include regular optical fibers with a Si-nc coating on the outside surface and hollow fibers where the coating is on the inner surface. The coatings were prepared using an inexpensive and straightforward solution-based process that yields a high-quality film, which can sustain high Q-factor whispering gallery modes.

Whispering gallery modes in silicon nanocrystal coated microcavities

Physica Status Solidi (a), 2009

We present photoluminescence studies of silicon-nanocrystal (Si-NC) coated microcavities. The par... more We present photoluminescence studies of silicon-nanocrystal (Si-NC) coated microcavities. The particular geometries studied are hollow fibers where there is a Si-NC coating in the inner surface and regular optical fibers and glass microspheres where the coating is on the outside surface. The coatings were prepared using an inexpensive and straightforward solution-based process that yields a high-quality film. The measured photoluminescence spectra from the resonators show high Q -factor (between 1200 and 2800) resonant modes that correspond with the whispering gallery modes expected from the confinement geometries. The presence of these modes is also an indication that the emission of the Si-NCs is coupled to the cavity. The combination of Si-NCs and optical microcavities with strong confinement has promising potential for applications like sensing, optical communications and may be a possible route toward a Si-NC laser. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Time-Resolved Spectroscopy of Single Excitons Bound to Pairs of Te Isoelectronic Impurity Centers in ZnSe

Tellurium impurity centers in ZnSe were individually probed with time-resolved photoluminescence ... more Tellurium impurity centers in ZnSe were individually probed with time-resolved photoluminescence (PL) spectroscopy. Resolution-limited peaks with an ultra-low spatial density originate in the recombination of excitons deeply bound to isolated nearest-neighbor isoelectronic Te pairs (Te2). This interpretation is confirmed by ab-initio calculations. The peaks reveal anti-bunched photon emission and a doublet structure polarized along [110] and [-110]. We analyze the time-resolved PL decay to clarify the role of the dark states in the spin relaxation and radiative recombination of single fine-structure split excitons.

Self-organized quantum-dot semiconductor microtube resonators and their integration on silicon photonics platforms

We present results on InGaAsP rolled-up microtube resonators with embedded InAs quantum dots with... more

Single rolled-up InGaAs/GaAs quantum dot microtubes integrated with silicon-on-insulator waveguides

Optics Express, 2011

We report on single rolled-up microtubes integrated with siliconon-insulator waveguides. Microtub... more We report on single rolled-up microtubes integrated with siliconon-insulator waveguides. Microtubes with diameters of ~7 μm, wall thicknesses of ~250 nm, and lengths greater than 100 μm are fabricated by selectively releasing a coherently strained InGaAs/GaAs quantum dot layer from the handling GaAs substrate. The microtubes are then transferred from their host substrate to silicon-on-insulator waveguides by an optical fiber abrupt taper. The Q-factor of the waveguide coupled microtube is measured to be 1.5×10 5 , the highest recorded for a semiconductor microtube cavity to date. The insertion loss and extinction ratio of the microtube are 1 dB and 34 dB respectively. By pumping the microtube with a 635 nm laser, the resonance wavelength is shifted by 0.7 nm. The integration of InGaAs/GaAs microtubes with silicon-on-insulator waveguides provides a simple, low loss, high extinction passive filter solution in the C+L band communication regime.

1.3 – 1.55 µm self-organized InAs quantum dot tube nanoscale lasers on silicon

We report on the design, fabrication, and characterization of rolled-up 1.3-1.5 μm InAs quantum d... more

Time-resolved photoluminescence spectroscopy of individual Te impurity centers in ZnSe

Physical Review B, 2006

Time-resolved photoluminescence ͑PL͒ measurements are carried out for the InGaAs quantum dots ͑QD... more Time-resolved photoluminescence ͑PL͒ measurements are carried out for the InGaAs quantum dots ͑QDs͒ grown on ͑001͒ and ͑311͒ oriented GaAs substrates. The detection energies scan the spectral region from the energy of the QD excitonic transition up to the wetting layer absorption edge. A convex-shaped decay of the PL signal in this region gives evidence of carrier relaxation through the continuum states below the wetting layer similar to a diffusion process. Strong dependence of the decay time on the excitation density observed for the QD ground-state PL is consistent with a presented theoretical model.

Decoherence processes during optical manipulation of excitonic qubits in semiconductor quantum dots

Physical Review B, 2005

Using photoluminescence spectroscopy, we have investigated the nature of Rabi oscillation damping... more Using photoluminescence spectroscopy, we have investigated the nature of Rabi oscillation damping during optical manipulation of excitonic qubits in self-assembled quantum dots. Rabi oscillations were recorded by varying the pulse amplitude for fixed pulse durations between 4 ps and 10 ps. Up to five periods are visible, making it possible to quantify the excitation dependent damping. We find that this damping is more pronounced for shorter pulse widths and show that its origin is the nonresonant excitation of carriers in the wetting layer, most likely involving bound-to-continuum and continuum-to-bound transitions.

Silicon nanocrystals on bottle resonators: Mode structure, loss mechanisms and emission dynamics

Optics Express, 2010

Bottle resonators can support high Q-factor whispering gallery modes (WGMs) and demonstrate a ric... more Bottle resonators can support high Q-factor whispering gallery modes (WGMs) and demonstrate a rich mode spectrum. Resonators were fabricated using a fiber tapering apparatus and were coated with a thin, smooth layer of luminescent silicon nanocrystals. The photoluminescence spectrum showed WGM peaks with Q-factors near 2,500; however, evanescent measurements showed that these modes are a composite of many modes with Q-factors exceeding 10 6 , the highest yet seen for a silicon-nanocrystalcoated microresonators. The mode structure showed strong polarization and sensitivity to position within the bottle resonator. An analysis of loss mechanisms establishes surface roughness scattering as the limiting factor in these nanocrystal-coated bottle resonators in the absence of excited carriers.

Resonance Fluorescence From a Coherently Driven Semiconductor Quantum Dot In a Cavity

Physical review letters, Jan 1, 2007

Determination of anisotropic dipole moments in self-assembled quantum dots using Rabi oscillations

Applied physics letters, Jan 1, 2004

Coherent Control of a V-Type Three-Level System In a Single Quantum Dot

Physical review letters, Jan 1, 2005

Decoherence for Classically Chaotic Quantum Maps

Physical Review E, Jan 1, 2002

Discrete Wigner functions and the phase space representation of quantum computers

Physics Letters A, Jan 1, 2002

Whispering Gallery Mode Microresonators As Polarization Converters

Optics …, Jan 1, 2007

Polarization conversion in a silica microsphere

Arxiv preprint arXiv: …, Jan 1, 2007

Observation of simultaneous fast and slow light

Physical Review A, Jan 1, 2008

Internal and external polarization memory loss in single quantum dots

… and Laser Science …, Jan 1, 2006

(Invited) Silicon Nanocrystals Coupled to High-Q Optical Microcavities: Theory and Applications

Time-Resolved Spectroscopy of Single Excitons Bound to Te Isoelectronic Pairs in ZnSe

… and Laser Science …, Jan 1, 2005

Mode structure in the luminescence of Si-nc in cylindrical microcavities

Physica E-low-dimensional Systems & Nanostructures, 2009

We present photoluminescence studies of silicon-nanocrystal (Si-nc)-coated cylindrical microcavit... more We present photoluminescence studies of silicon-nanocrystal (Si-nc)-coated cylindrical microcavities. The particular geometries investigated include regular optical fibers with a Si-nc coating on the outside surface and hollow fibers where the coating is on the inner surface. The coatings were prepared using an inexpensive and straightforward solution-based process that yields a high-quality film, which can sustain high Q-factor whispering gallery modes.

Whispering gallery modes in silicon nanocrystal coated microcavities

Physica Status Solidi (a), 2009

We present photoluminescence studies of silicon-nanocrystal (Si-NC) coated microcavities. The par... more We present photoluminescence studies of silicon-nanocrystal (Si-NC) coated microcavities. The particular geometries studied are hollow fibers where there is a Si-NC coating in the inner surface and regular optical fibers and glass microspheres where the coating is on the outside surface. The coatings were prepared using an inexpensive and straightforward solution-based process that yields a high-quality film. The measured photoluminescence spectra from the resonators show high Q -factor (between 1200 and 2800) resonant modes that correspond with the whispering gallery modes expected from the confinement geometries. The presence of these modes is also an indication that the emission of the Si-NCs is coupled to the cavity. The combination of Si-NCs and optical microcavities with strong confinement has promising potential for applications like sensing, optical communications and may be a possible route toward a Si-NC laser. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Time-Resolved Spectroscopy of Single Excitons Bound to Pairs of Te Isoelectronic Impurity Centers in ZnSe

Tellurium impurity centers in ZnSe were individually probed with time-resolved photoluminescence ... more Tellurium impurity centers in ZnSe were individually probed with time-resolved photoluminescence (PL) spectroscopy. Resolution-limited peaks with an ultra-low spatial density originate in the recombination of excitons deeply bound to isolated nearest-neighbor isoelectronic Te pairs (Te2). This interpretation is confirmed by ab-initio calculations. The peaks reveal anti-bunched photon emission and a doublet structure polarized along [110] and [-110]. We analyze the time-resolved PL decay to clarify the role of the dark states in the spin relaxation and radiative recombination of single fine-structure split excitons.

Self-organized quantum-dot semiconductor microtube resonators and their integration on silicon photonics platforms

We present results on InGaAsP rolled-up microtube resonators with embedded InAs quantum dots with... more

Single rolled-up InGaAs/GaAs quantum dot microtubes integrated with silicon-on-insulator waveguides

Optics Express, 2011

We report on single rolled-up microtubes integrated with siliconon-insulator waveguides. Microtub... more We report on single rolled-up microtubes integrated with siliconon-insulator waveguides. Microtubes with diameters of ~7 μm, wall thicknesses of ~250 nm, and lengths greater than 100 μm are fabricated by selectively releasing a coherently strained InGaAs/GaAs quantum dot layer from the handling GaAs substrate. The microtubes are then transferred from their host substrate to silicon-on-insulator waveguides by an optical fiber abrupt taper. The Q-factor of the waveguide coupled microtube is measured to be 1.5×10 5 , the highest recorded for a semiconductor microtube cavity to date. The insertion loss and extinction ratio of the microtube are 1 dB and 34 dB respectively. By pumping the microtube with a 635 nm laser, the resonance wavelength is shifted by 0.7 nm. The integration of InGaAs/GaAs microtubes with silicon-on-insulator waveguides provides a simple, low loss, high extinction passive filter solution in the C+L band communication regime.

1.3 – 1.55 µm self-organized InAs quantum dot tube nanoscale lasers on silicon

We report on the design, fabrication, and characterization of rolled-up 1.3-1.5 μm InAs quantum d... more

Time-resolved photoluminescence spectroscopy of individual Te impurity centers in ZnSe

Physical Review B, 2006

Time-resolved photoluminescence ͑PL͒ measurements are carried out for the InGaAs quantum dots ͑QD... more Time-resolved photoluminescence ͑PL͒ measurements are carried out for the InGaAs quantum dots ͑QDs͒ grown on ͑001͒ and ͑311͒ oriented GaAs substrates. The detection energies scan the spectral region from the energy of the QD excitonic transition up to the wetting layer absorption edge. A convex-shaped decay of the PL signal in this region gives evidence of carrier relaxation through the continuum states below the wetting layer similar to a diffusion process. Strong dependence of the decay time on the excitation density observed for the QD ground-state PL is consistent with a presented theoretical model.

Decoherence processes during optical manipulation of excitonic qubits in semiconductor quantum dots

Physical Review B, 2005

Using photoluminescence spectroscopy, we have investigated the nature of Rabi oscillation damping... more Using photoluminescence spectroscopy, we have investigated the nature of Rabi oscillation damping during optical manipulation of excitonic qubits in self-assembled quantum dots. Rabi oscillations were recorded by varying the pulse amplitude for fixed pulse durations between 4 ps and 10 ps. Up to five periods are visible, making it possible to quantify the excitation dependent damping. We find that this damping is more pronounced for shorter pulse widths and show that its origin is the nonresonant excitation of carriers in the wetting layer, most likely involving bound-to-continuum and continuum-to-bound transitions.

Silicon nanocrystals on bottle resonators: Mode structure, loss mechanisms and emission dynamics

Optics Express, 2010

Bottle resonators can support high Q-factor whispering gallery modes (WGMs) and demonstrate a ric... more Bottle resonators can support high Q-factor whispering gallery modes (WGMs) and demonstrate a rich mode spectrum. Resonators were fabricated using a fiber tapering apparatus and were coated with a thin, smooth layer of luminescent silicon nanocrystals. The photoluminescence spectrum showed WGM peaks with Q-factors near 2,500; however, evanescent measurements showed that these modes are a composite of many modes with Q-factors exceeding 10 6 , the highest yet seen for a silicon-nanocrystalcoated microresonators. The mode structure showed strong polarization and sensitivity to position within the bottle resonator. An analysis of loss mechanisms establishes surface roughness scattering as the limiting factor in these nanocrystal-coated bottle resonators in the absence of excited carriers.

Resonance Fluorescence From a Coherently Driven Semiconductor Quantum Dot In a Cavity

Physical review letters, Jan 1, 2007

Determination of anisotropic dipole moments in self-assembled quantum dots using Rabi oscillations

Applied physics letters, Jan 1, 2004

Coherent Control of a V-Type Three-Level System In a Single Quantum Dot

Physical review letters, Jan 1, 2005

Decoherence for Classically Chaotic Quantum Maps

Physical Review E, Jan 1, 2002

Discrete Wigner functions and the phase space representation of quantum computers

Physics Letters A, Jan 1, 2002

Whispering Gallery Mode Microresonators As Polarization Converters

Optics …, Jan 1, 2007

Polarization conversion in a silica microsphere

Arxiv preprint arXiv: …, Jan 1, 2007

Observation of simultaneous fast and slow light

Physical Review A, Jan 1, 2008

Internal and external polarization memory loss in single quantum dots

… and Laser Science …, Jan 1, 2006

(Invited) Silicon Nanocrystals Coupled to High-Q Optical Microcavities: Theory and Applications

Time-Resolved Spectroscopy of Single Excitons Bound to Te Isoelectronic Pairs in ZnSe

… and Laser Science …, Jan 1, 2005