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Giovannini, Marcella

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Giovannini, Marcella
Affiliation principale
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Ancien.ne collaborateur.trice
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https://libra.unine.ch/handle/123456789/32206

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  • Publication
    Accès libre
    Applications for quantum cascade lasers and detectors in mid-infrared high-resolution heterodyne astronomy
    (2008)
    Krötz, Peter
    ;
    Stupar, D.
    ;
    Krieg, J.
    ;
    Sonnabend, Guido
    ;
    Sornig, M.
    ;
    Giorgetta, Fabrizio R.
    ;
    Baumann, Esther
    ;
    Giovannini, Marcella 
    ;
    Hoyler, Nicolas
    ;
    Hofstetter, Daniel 
    ;
    Schieder, R.
    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.
  • Publication
    Accès libre
    16.5 µm quantum cascade detector using miniband transport
    (2007)
    Giorgetta, Fabrizio R.
    ;
    Baumann, Esther
    ;
    Graf, Marcel
    ;
    Ajili, Lassaad
    ;
    Hoyler, Nicolas
    ;
    Giovannini, Marcella 
    ;
    Faist, Jérôme
    ;
    Hofstetter, Daniel 
    ;
    Krötz, Peter
    ;
    Sonnabend, Guido
    The authors report on an InP based photovoltaic quantum cascade detector operating at 16.5 µm and using miniband-based vertical transport. This concept allowed the construction of a longitudinal optical phonon extraction stair with two rungs without touching on a high device resistance. At 10 K, they observed a responsivity of 1.72 mA/W and a Johnson noise limited detectivity of 2.2×109 Jones. Altogether, this design resulted in detection at temperatures of up to 90 K with a lower bandwidth limit of 200 MHz imposed by the measurement setup.
  • Publication
    Accès libre
    Room temperature, continuous wave operation of distributed feedback quantum cascade lasers with widely spaced operation frequencies
    (2006)
    Wittmann, Andreas
    ;
    Giovannini, Marcella 
    ;
    Faist, Jérôme
    ;
    Hvozdara, Lubos
    ;
    Blaser, Stéphane
    ;
    Hofstetter, Daniel 
    ;
    Gini Emilio
    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.
  • Publication
    Accès libre
    InP-based quantum cascade detectors in the mid-infrared
    (2006)
    Graf, Marcel
    ;
    Hoyler, Nicolas
    ;
    Giovannini, Marcella 
    ;
    Faist, Jérôme
    ;
    Hofstetter, Daniel 
    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.