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174 results on '"Giovannini, Marcella"'

1. High power spatial single-mode quantum cascade lasers at 8.9 $\mu$m

Author

Forget, Sebastien, Faugeras, Clement, Bengloan, Jean Yves, Calligaro, Michel, Parillaud, Olivier, Giovannini, Marcella, Faist, Jerome, and Sirtori, Carlo

Subjects
Physics - Optics
Abstract

High performance of InP-based quantum cascade lasers emitting at $\lambda$ ~ 9$\mu$m are reported. Thick electroplated gold layer was deposited on top of the laser to improve heat dissipation. With one facet high reflection coated, the devices produce a maximum output power of 175mW at 40% duty cycle at room temperature and continuous-wave operation up to 278K.

Published
2006

2. Mid-Infrared Single Photon Counting

Author

Temporao, Guilherme, Tanzilli, Sebastien, Zbinden, Hugo, Gisin, Nicolas, Aellen, Thierry, Giovannini, Marcella, and Faist, Jerome

Subjects
Quantum Physics
Abstract

We report a procedure to detect mid-infrared single photons at 4.65 um via a two-stage scheme based on Sum Frequency Generation, using a Periodically Poled Lithium Niobate (PPLN) nonlinear crystal and a Silicon Avalanche Photodiode. An experimental investigation shows that, in addition to a high timing resolution, this technique yields a detection sensitivity of 1.24 pW with 63mW of net pump power., Comment: 9 pages, 2 figures, submitted to Optics Letters

Published
2005
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4. Time-resolved investigations of electronic transport dynamics in quantum cascade lasers based on diagonal lasing transitions

Author

Hyunyong Choi, Diehl, Laurent, Zong-Kwei Wu, Giovannini, Marcella, Faist, Jerome, Capasso, Federico, and Norris, Theodore B.

Subjects
Electron transport -- Analysis, Monte Carlo method -- Usage, Semiconductor lasers -- Evaluation, Waveguides -- Analysis, Business, Computers, Electronics, Electronics and electrical industries
Abstract

The nature of electronic transport in quantum cascade lasers (QCLs) is examined by using an ultrafast time-resolved, degenerate, pump-probe optical method. Subpicosecond dynamics due to carrier heating in the upper subband are isolated and the polarization anisotropy in the active waveguide is negligible in the pump-probe data.

Published
2009

5. High-performance bound-to-continuum quantum-cascade lasers for broad-gain applications

Author

Wittmann, Andreas, Gresch, Tobias, Gini, Emilio, Hvozdara, Lubos, Hoyler, Nicolas, Giovannini, Marcella, and Faist, Jerome

Subjects
Quantum electronics -- Design and construction, Quantum electronics -- Comparative analysis, Semiconductor lasers -- Design and construction, Semiconductor lasers -- Analysis, Business, Computers, Electronics, Electronics and electrical industries
Abstract

A high performance continuous-wave (CW) quantum-cascade laser based on the bound-to-continuum active region design is presented. An internal differential quantum efficiency of 71 percent and a wallplug efficiency of 2.0 percent are observed at 30 degree Celsius.

Published
2008

6. Multi-wavelength operation and vertical emission in THz quantum-cascade lasers

Author

Scalari, Giacomo, Sirigu, Lorenzo, Terazzi, Romain, Walther, Christoph, Amanti, Maria I., Giovannini, Marcella, Hoyler, Nicholas, Faist, Jerome, Sadowski, Marcin L., Beere, Harvy, Ritche, David, Dunbar, L. Andrea, and Houdre, Romuald

Subjects
Magnetic fields -- Measurement, Photonics -- Research, Quantum theory -- Analysis, Physics
Abstract

A multiwavelength quantum cascade laser (QCL) operating at 1.39 and 2.3 THz in a strong magnetic field is studied. The possibility of achieving vertical emission from QCL by using an optical cavity formed by two-dimensional photonic crystal operating at 3.7 THz is discussed.

Published
2007

7. Fabrication and characterization of molecular beam epitaxy grown thin-film GaAs waveguides for mid-infrared evanescent field chemical sensing

Author

Charlton, Christy, Giovannini, Marcella, Faist, Jerome, and Mizaikoff, Boris

Subjects
Epitaxy -- Research, Gallium arsenide -- Structure, Gallium arsenide -- Optical properties, Dielectric films -- Structure, Dielectric films -- Optical properties, Thin films -- Structure, Thin films -- Optical properties, Waveguides -- Usage, Chemistry
Abstract

Thin-film GaAs waveguides were designed and fabricated by molecular beam epitaxy for use in mid-infrared (MIR) evanescent field liquid sensing. Waveguides were designed to facilitate the propagation of a single mode at a wavelength of 10.3 [micro]m emitted from a distributed feedback quantum cascade laser, which overlaps with molecular selective absorption features of acetic anhydride. The characterization of the waveguides shows transmission across a broad MIR band. Evanescent field absorption measurements indicate a significant sensitivity enhancement in contrast to multimode planar silver halide waveguides.

Published
2006

8. High-power room temperature emission quantum cascade lasers at Lambda=9 mu m

Author

Faugeras, Clement, Forget, Sebastien, Boer-Duchemin, Elizabeth, Page, Hideaki, Bengloan, Jean-Yves, Parillaud, Olivier, Calligaro, Michel, Sirtori, Carlo, Giovannini, Marcella, and Faist, Jerome

Subjects
High power lasers -- Design and construction, Indium -- Optical properties, Phosphorus compounds -- Optical properties, Business, Computers, Electronics, Electronics and electrical industries
Abstract

Different techniques for processing InP-based lambda =9 mu m quantum cascade lasers which improve the thermal dissipation in the device are presented. Lasers with a thick electroplated gold layer show CW operation up to 278 K and 1 W of optical power at 280 K in pulsed operation and with such a process, the thermal characteristics of the lasers are improved with an output average power of 174 mW at a duty cycle of 40% measured at 10 degree centigrade for 2-mm-long laser.

Published
2005

9. Imaging at 3.4 THz with a quantum-cascade laser

Author

Chamberlin, Danielle R., Robrish, Peter R., Trutna, William R., Scalari, Giacomo, Giovannini, Marcella, Ajili, Lassaad, and Faist, Jerome

Subjects
Optics -- Research, Lasers -- Research, Laser, Astronomy, Physics
Abstract

We have assembled a single-frequency imaging system at 3.4 THz with a quantum-cascade laser. Images of electronic and biological applications are demonstrated. We operate the laser with a peak output power of 2.5 mW at a 7% duty cycle and a 22 K operating temperature. The minimum spot size is 340 [micro]m. The signal is detected with a single-element deuterated triglycine sulfate detector, and images are captured by scanning of the sample. OCIS codes: 140.3070, 110.2970.

Published
2005

11. Second harmonic generation in (111)-oriented InP-based quantum cascade laser.

Author

Giovannini, Marcella, Beck, Mattias, Hoyler, Nicolas, and Faist, Jérôme

Subjects
*SECOND harmonic generation, *INDIUM, *PHOSPHORUS, *LASERS, *NONLINEAR optics
Abstract

We show the realization of quantum cascade lasers (QCL) grown on (111)-oriented InP substrates instead of the usual (100)-oriented surface. Growth along [111] orientation allows the excitation of the nonlinear susceptibility for the transverse magnetic wave produced by the QCL. Two devices were realized, at 6 and 10 μm wavelengths. They are compared with the same structures grown on the usual (100)-oriented surface. Second harmonic generation is demonstrated in one of the devices. [ABSTRACT FROM AUTHOR]

Published
2007
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12. Doping in quantum cascade lasers. I. InAlAs–InGaAs/InP midinfrared devices.

Author

Aellen, Thierry, Beck, Mattias, Hoyler, Nicolas, Giovannini, Marcella, Faist, Jérôme, and Gini, Emilio

Subjects
DOPED semiconductors, LASER beams, QUANTUM tunneling, SPECTRUM analysis, PHONONS
Abstract

The effect of the doping densities on the performance of 9 μm InAlAs–InGaAs/InP quantum cascade lasers is presented. Doping densities varying between 1.0×1011 and 2.6×1011 cm-2 were investigated. In this range, a linear increase in both threshold and maximum current density with sheet carrier density is observed. These effects are explained using a model based on resonant tunneling transport and rate equations. [ABSTRACT FROM AUTHOR]

Published
2006
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13. Doping in quantum cascade lasers. II. GaAs/[Al.sub.0.15][Ga.sub.0.85]As terahertz devices

Author

Ajili, Lassaad, Scalari, Giacomo, Giovannini, Marcella, Hoyler, Nicolas, and Faist, Jerome

Subjects
Gallium arsenide -- Optical properties, Optical waveguides -- Usage, Semiconductor doping -- Analysis, Semiconductor lasers -- Optical properties, Physics
Abstract

The performances of GaAs/[Al.sub.0.15][Ga.sub.0.85]As terahertz quantum cascade lasers based on a bound-to-continuum transition are examined as a function of injector doping. A linear dependence between threshold current and doping is observed and it has agreed well with the expected increase of waveguide losses due to free carrier absorption.

Published
2006

14. Doping in quantum cascade lasers. II. GaAs/Al0.15Ga0.85As terahertz devices.

Author

Ajili, Lassaad, Scalari, Giacomo, Giovannini, Marcella, Hoyler, Nicolas, and Faist, Jérôme

Subjects
DOPED semiconductors, LASER beams, SEMICONDUCTOR lasers, SECONDARY ion mass spectrometry, WAVEGUIDES
Abstract

The performances of GaAs/Al0.15Ga0.85As terahertz quantum cascade lasers based on a bound-to-continuum transition are investigated as a function of injector doping. A linear dependence between threshold current and doping is found and agrees with the expected increase of waveguide losses due to free carrier absorption. [ABSTRACT FROM AUTHOR]

Published
2006
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15. LO-phonon emission by hot electrons in terahertz quantum cascade lasers

Author

Péré-Laperne, Nicolas, de Vaulchier, Louis-Anne, Guldner, Yves, Scalari, Giacomo, Giovannini, Marcella, Faist, Jérôme, Vasanelli, Angela, Dhillon, Sukhdeep, Sirtori, Carlo, Laboratoire Pierre Aigrain (LPA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Physics, Université de Neuchâtel (UNINE), Laboratoire Matériaux et Phénomènes Quantiques (MPQ (UMR_7162)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and de Vaulchier, Louis-Anne

Subjects
[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]
Abstract

Recently, a new design of Quantum Cascade Lasers (QCL) operating in the terahertz (THz) domain that combines the advantages of the bound-to-continuum approach together with the use of a LO-phonon resonance was proposed [1]. In this structure, the extraction miniband of the bound-to-continuum transition is aligned resonantly with the first excited state of a large coupled quantum well which exhibits a transition at roughly the LO-phonon energy hwLO. This large energy separation was supposed to significantly reduce the lower state lifetime by allowing optical phonon scattering of the electrons and also to reduce the thermal backfilling of the lower state. We present measurements performed on that particular structure under a strong magnetic field applied parallel to the growth axis. Each level of the QCL is split into a series of Landau levels (LLs). As previously reported, the lifetime of the upper state of the laser transition, and thus the output power, can be modulated by varying the magnetic field. A strong increase of the scattering rate, and therefore a output power minimum, is observed when two LLs are brought into resonance, since in that case electrons can scatter elastically, essentially as a result of the interface roughness. This leads to dramatic oscillations of the emission power which vary as B-1. Besides these features, a second series of oscillations is also clearly observed in this structure. Such minima cannot be accounted by inter-LL resonances or by resonant electron-electron scattering (Auger like effect) as previously observed in different structures. We show that they can be explained by LO-phonon emission from hot electrons injected in the LLs of the upper level. For critical values of the magnetic field, these electrons can resonantly emit one LO-phonon and relax directly to the fundamental LL of the laser transition, leading to a minimum in the output power. We are developing a simple model to calculate the magnetic-field dependence of the upper state lifetime. The first predictions of this model, including both the interface roughness scattering and the LO-phonon emission, account very well for the experimental data.

Published
2006

17. High power spatial single-mode quantum cascade lasers at 8.9 µm

Author

Forget, Sebastien, Faugeras, Clement, Bengloan, Jean Yves, Calligaro, Michel, Parillaud, Olivier, Giovannini, Marcella, Faist, Jerome, Sirtori, Carlo, Laboratoire Matériaux et Phénomènes Quantiques (MPQ (UMR_7162)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Thales Research and Technology [Palaiseau], THALES, Institute of Physics (INSTITUTE OF PHYSICS, NEUCHATEL), and Université de Neuchâtel (UNINE)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], FOS: Physical sciences, Physics::Optics, quantum cascade laser, Optics (physics.optics), Physics - Optics
Abstract

High performance of InP-based quantum cascade lasers emitting at $\lambda$ ~ 9$\mu$m are reported. Thick electroplated gold layer was deposited on top of the laser to improve heat dissipation. With one facet high reflection coated, the devices produce a maximum output power of 175mW at 40% duty cycle at room temperature and continuous-wave operation up to 278K.

Published
2005

18. Applications for quantum cascade lasers and detectors in mid-infrared high-resolution heterodyne astronomy

Author

Krötz, Peter, Stupar, D., Krieg, J., Sonnabend, Guido, Sornig, M., Giorgetta, Fabrizio R., Baumann, Esther, Giovannini, Marcella, Hoyler, Nicolas, Hofstetter, Daniel, Schieder, R., Krötz, Peter, Stupar, D., Krieg, J., Sonnabend, Guido, Sornig, M., Giorgetta, Fabrizio R., Baumann, Esther, Giovannini, Marcella, Hoyler, Nicolas, Hofstetter, Daniel, and Schieder, R.

Abstract

Quantum cascade (QC) structures, for both emitting and detecting mid-infrared radiation, are powerful devices for spectroscopy. QC lasers (QCLs), which have been built for nearly 15 years, already play the leading role in certain wavelength regions. QC detectors (QCDs) are a fairly new development, which has been evolving from the QCL research. In high-resolution heterodyne spectrometers for astronomy, such as the Cologne tuneable heterodyne infrared spectrometer (THIS), QC devices help to open new windows to space as discussed in this paper. We will briefly review the use of QC devices in THIS, show recent results in measuring planetary atmospheric dynamics and give an outlook to astronomical goals for the future.

Published
2008

19. Room temperature, continuous wave operation of distributed feedback quantum cascade lasers with widely spaced operation frequencies

Author

Wittmann, Andreas, Giovannini, Marcella, Faist, Jérôme, Hvozdara, Lubos, Blaser, Stéphane, Hofstetter, Daniel, Gini Emilio, Wittmann, Andreas, Giovannini, Marcella, Faist, Jérôme, Hvozdara, Lubos, Blaser, Stéphane, Hofstetter, Daniel, and Gini Emilio

Abstract

Lasing properties of room temperature, continuous wave operated distributed feedback (DFB) quantum cascade lasers are reported. A bound-to-continuum active region was used to generate a broad gain spectrum. As a result, first-order DFB lasers employing different periods allowed us to achieve single mode continuous wave emission at several wavelengths ranging from 7.7 to 8.3 µm at a temperature of +30 °C. The frequency span corresponds to 8% of the center frequency.

Published
2008

20. InP-based quantum cascade detectors in the mid-infrared

Author

Graf, Marcel, Hoyler, Nicolas, Giovannini, Marcella, Faist, Jérôme, Hofstetter, Daniel, Graf, Marcel, Hoyler, Nicolas, Giovannini, Marcella, Faist, Jérôme, and Hofstetter, Daniel

Abstract

We present two InP-based quantum cascade detectors (QCDs) in the mid-infrared wavelength range. Their narrow band detection spectra are centered at 5.3 and 9 µm. A vertical intersubband transition followed by a carefully designed extraction cascade, which is adapted to the LO-phonon energy, leads to 10 K responsivities R of 3.2 and 9.0 mA/W and background limited detectivities D*BLIP of 2×108 and 3×109 Jones, for the 5.3 and the 9 µm devices, respectively. Detection has been observed up to device temperatures of 300 K (RT), albeit reasonable performance is restricted to temperatures below 150 K (5.3 µm) and 70 K (9 µm). Designed for zero bias operation, QCDs do not produce any dark current and therefore do not suffer from dark current noise and capacitance saturation at long integration times, making them ideal devices for large focal plane arrays.

Published
2008

21. Femtosecond pump-probe studies of carrier transport and gain dynamics in quantum cascade lasers

Author

Center for Ultrafast Optical Science and Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109-2099, USA, Center for Ultrafast Optical Science and Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109-2099, USA ; Phone: +1-734-7649269, Fax: 1-734-7634876, Institute of Physics, University of NeuchÂtel, 2000 NeuchÂtel, Switzerland, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA, Choi, Hyunyong, Diehl, Laurent, Giovannini, Marcella, Faist, Jérôme, Capasso, Federico, Norris, Theodore B., Center for Ultrafast Optical Science and Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109-2099, USA, Center for Ultrafast Optical Science and Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109-2099, USA ; Phone: +1-734-7649269, Fax: 1-734-7634876, Institute of Physics, University of NeuchÂtel, 2000 NeuchÂtel, Switzerland, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA, Choi, Hyunyong, Diehl, Laurent, Giovannini, Marcella, Faist, Jérôme, Capasso, Federico, and Norris, Theodore B.

Abstract

Time-resolved pump-probe differential transmission measurements have been performed on various sets of quantum cascade lasers below and above threshold. Bias-, temperature-, and polarization dependent studies enable a comprehensive understanding of the gain dynamics to be possible in terms of tunneling, transport, and coupling with the intra-cavity photon density. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Published
2008

37. 16.5μm quantum cascade detector using miniband transport

Author

Giorgetta, Fabrizio R., primary, Baumann, Esther, additional, Graf, Marcel, additional, Ajili, Lassaad, additional, Hoyler, Nicolas, additional, Giovannini, Marcella, additional, Faist, Jérôme, additional, Hofstetter, Daniel, additional, Krötz, Peter, additional, and Sonnabend, Guido, additional

Published
2007
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41. Bloch gain in quantum cascade lasers

Author

Terazzi, Romain, primary, Gresch, Tobias, additional, Giovannini, Marcella, additional, Hoyler, Nicolas, additional, Sekine, Norihiko, additional, and Faist, Jérôme, additional

Published
2007
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50. Characterization of a near-room-temperature, continuous-wave quantum cascade laser for long-term, unattended monitoring of nitric oxide in the atmosphere

Author

Nelson, David D., primary, McManus, J. Barry, additional, Herndon, Scott C., additional, Shorter, Joanne H., additional, Zahniser, Mark S., additional, Blaser, Stéphane, additional, Hvozdara, Lubos, additional, Muller, Antoine, additional, Giovannini, Marcella, additional, and Faist, Jérôme, additional

Published
2006
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