Carlo Sirtori

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A semiconductor injection laser that differs in a fundamental way from diode lasers has been demonstrated. It is built out of quantum semiconductor structures that were grown by molecular beam epitaxy and designed by band structure engineering. Electrons streaming down a potential staircase sequentially emit photons at the steps. The steps consist of(More)
We study the properties of Expected Shortfall from the point of view of financial risk management. This measure — which emerges as a natural remedy in some cases where VaR is not able to distinguish portfolios which bear different levels of risk — is indeed shown to have much better properties than VaR. We show in fact that unlike VaR this variable is in(More)
Neural networks are trained to estimate the germination percentages of Plasmopara viticola oospores, overwintered in natural conditions in two viticultural areas in northern Italy, by using climatic (temperature and rainfall) data, as well as the previous germination measurement, as input variables. The 288 available patterns consist of a set of selected(More)
using resonant nonlinearities Julien Madéo, Pierrick Cavalié, Joshua R. Freeman, Nathan Jukam, Jean Maysonnave, Kenneth Maussang, Harvey. E. Beere, David. A. Ritchie, Carlo Sirtori, Jérôme Tignon and Sukhdeep S. Dhillon Laboratoire Pierre Aigrain, Ecole Normale Supérieure, UMR 8551 CNRS, Université P. et M. Curie, Université D. Diderot, 24 rue Lhomond,(More)
The regime of ultrastrong light-matter interaction has been investigated theoretically and experimentally, using zero-dimensional electromagnetic resonators coupled with an electronic transition between two confined states of a semiconductor quantum well. We have measured a splitting between the coupled modes that amounts to 48% of the energy transition,(More)
Lasers are usually described by their output frequency and intensity. However, laser operation is an inherently nonlinear process. Knowledge about the dynamic behaviour of lasers is thus of great importance for detailed understanding of laser operation and for improvement in performance for applications. Of particular interest is the time domain within the(More)
We have realized an electroluminescent device operating in the light-matter strong-coupling regime based on a GaAs/AlGaAs quantum cascade structure embedded in a planar microcavity. At zero bias, reflectivity measurements show a polariton anticrossing between the intersubband transition and the cavity mode. Under electrical injection the spectral features(More)
We have demonstrated that a metal-dielectric-metal microcavity combined with quantum well intersubband transitions is an ideal system for the generation of cavity polariton states in the terahertz region. The metallic cavity has highly confined radiation modes that can be tuned in resonance with the intersubband transition. In this system we were able to(More)
Laser waveguides based on surface plasmons at a metal-semiconductor interface have been demonstrated by use of quantum cascade (QC) lasers emitting in the 8-11.5-microm wavelength range. The guided modes are transverse magnetic polarized surface waves that propagate at the metal (Pd or Ti-Au)-semiconductor interface between the laser top contact and the(More)