Showing posts with label Philippe Nouvel. Show all posts
Showing posts with label Philippe Nouvel. Show all posts

Friday, September 14, 2018

Abstract-Out-of-Equilibrium Collective Oscillation as Phonon Condensation in a Model Protein


Ilaria Nardecchia, Jeremie Torres, Mathias Lechelon, Valeria Giliberti, Michele Ortolani, Philippe Nouvel, Matteo Gori, Yoann Meriguet, Irene Donato, Jordane Preto, Luca Varani, James Sturgis, Marco Pettini


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We describe the activation of out-of-equilibrium collective oscillations of a macromolecule as a classical phonon condensation phenomenon. If a macromolecule is modeled as an open system—that is, it is subjected to an external energy supply and is in contact with a thermal bath to dissipate the excess energy—the internal nonlinear couplings among the normal modes make the system undergo a nonequilibrium phase transition when the energy input rate exceeds a threshold value. This transition takes place between a state where the energy is incoherently distributed among the normal modes and a state where the input energy is channeled into the lowest-frequency mode entailing a coherent oscillation of the entire molecule. The model put forward in the present work is derived as the classical counterpart of a quantum model proposed a long time ago by Fröhlich in an attempt to explain the huge speed of enzymatic reactions. We show that such a phenomenon is actually possible. Two different and complementary THz near-field spectroscopic techniques—a plasmonic rectenna and a microwire near-field probe—have been used in two different labs to eliminate artifacts. By considering an aqueous solution of a model protein, the bovine serum albumin, we find that this protein displays a remarkable absorption feature around 0.314 THz, when driven in a stationary out-of-thermal equilibrium state by means of optical pumping. The experimental outcomes are in very good qualitative agreement with the theory developed in the first part of the paper and in excellent quantitative agreement with the theoretical result, allowing us to identify the observed spectral feature with a collective oscillation of the entire molecule.
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Thursday, July 26, 2018

Abstract-Out-of-equilibrium collective oscillation as phonon condensation in a model protein


Ilaria Nardecchia, Jeremie Torres, Mathias Lechelon, Valeria Giliberti, Michele Ortolani, Philippe Nouvel, Matteo Gori, Yoann Meriguet, Irene Donato, Jordane Preto, Luca Varani, James Sturgis, and Marco Pettini

https://journals.aps.org/prx/accepted/2b071K1dY6a1e20d62871a345233bd6dc5eefd37f

In the first part of the present paper (theoretical), the activation of out-of-equilibrium collective oscillations of a macromolecule is described as a classical phonon condensation phenomenon. If a macromolecule is modeled as an open system, that is, it is subjected to an external energy supply and is in contact with a thermal bath to dissipate the excess energy, the internal nonlinear couplings among the normal modes make the system undergo a non-equilibrium phase transition when the energy input rate exceeds a threshold value. This transition takes place between a state where the energy is incoherently distributed among the normal modes, to a state where the input energy is channeled into the lowest frequency mode entailing a coherent oscillation of the entire molecule. The model put forward in the present work is derived as the classical counterpart of a quantum model proposed long time ago by H. Fr\"ohlich in the attempt to explain the huge speed of enzymatic reactions. In the second part of the present paper (experimental), we show that such a phenomenon is actually possible. Two different and complementary THz near-field spectroscopic techniques, a plasmonic rectenna, and a micro-wire near-field probe, have been used in two different labs to get rid of artefacts. By considering a aqueous solution of a model protein, the BSA (Bovine Serum Albumin), we found that this protein displays a remarkable absorption feature around 0.314 THz, when driven in a stationary out-of-thermal equilibrium state by means of optical pumping. The experimental outcomes are in very good qualitative agreement with the theory developed in the first part, and in excellent quantitative agreement with a theoretical result allowing to identify the observed spectral feature with a collective oscillation of the entire molecule.

Friday, October 13, 2017

AbstractTHz Detection and Imaging using Graphene Ballistic Rectifiers



Gregory Hunter AutonDmytro Butjiawei ZhangErnie W. HillDominique CoquillatChristophe ConsejoPhilippe NouvelWojciech KnapLuca VaraniFrederic TeppeJeremie Torres, and Aimin Song

http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.7b03625?journalCode=nalefd

A graphene ballistic rectifier is used in conjunction with an antenna to demonstrate a rectenna as a terahertz (THz) detector. A small-area (<1 μm2) local gate is used to adjust the Fermi level in the device to optimise the output while minimising the impact on the cut-off frequency. The device operates in both n- and p-type transport regimes and shows a peak extrinsic responsivity of 764 V/W and a corresponding noise equivalent power of 34 pW Hz-1/2 at room temperature with no indications of a cut-off frequency up to 0.45 THz. The device also demonstrates a linear response for more than three orders of magnitude of input power due to its zero threshold voltage, quadratic current-voltage characteristics and high saturation current. Finally, the device is used to take an image of an optically opaque object at 0.685 THz, demonstrating potential in both medical and security imaging applications.

Saturday, November 19, 2016

Abstract-Wide modulation bandwidth terahertz detection in 130 nm CMOS technology


1 ECSE Department, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
2 ECE Department, Ain Shams University, 11566 Cairo, Egypt
3 Institut d’électronique et des Systèmes, UMR 5214 CNRS-Université de Montpellier, 34095 Montpellier, France
4 Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, 34095 Montpellier, France 

Design, manufacturing and measurements results for silicon plasma wave transistors based wireless communication wideband receivers operating at 300 GHz carrier frequency are presented. We show the possibility of Si-CMOS based integrated circuits, in which by: (i) specific physics based plasma wave transistor design allowing impedance matching to the antenna and the amplifier, (ii) engineering the shape of the patch antenna through a stacked resonator approach and (iii) applying bandwidth enhancement strategies to the design of integrated broadband amplifier, we achieve an integrated circuit of the 300 GHz carrier frequency receiver for wireless wideband operation up to/over 10 GHz. This is, to the best of our knowledge, the first demonstration of low cost 130 nm Si-CMOS technology, plasma wave transistors based fast/wideband integrated receiver operating at 300 GHz atmospheric window. These results pave the way towards future large scale (cost effective) silicon technology based terahertz wireless communication receivers.