In the headlines
A comprehensive review on the state of the art of THz quantum cascade lasers has been recently authored by Carlo Sirtori and Stefano Barbieri, members of our laboratory. The article has been published last September on Nature Photonics in a special issue with focus on “Advances in terahertz optics”.
This review, entitled “Wave engineering with THz quantum cascade lasers” discusses the concepts and techniques that have been implemented to control spectral and spatial beam properties of these (...)
Photonics is to play a central role in the development of quantum information and communication technologies. Integrability, room temperature operation and compatibility with the telecom network constitute some key issues for future quantum components. A. Orieux and colleagues at ‘Matériaux et Phénomènes Quantiques’ Laboratory (Paris Diderot University and CNRS) in the framework of a collaboration with Laboratory LPN and ISMO report in Physical Review Letters the first III-V semiconductor source (...)
A review of recent theoretical and experimental advances in the fundamental understanding and active control of quantum fluids of light in nonlinear optical systems has been published in Reviews of Modern Physics. In the presence of effective photon-photon interactions induced by the optical nonlinearity of the medium, a many-photon system can behave collectively as a quantum fluid with a number of novel fascinating features stemming from its intrinsically non-equilibrium nature.
Photon absorption in a quantum structure is related to a transition between two electronic states of the system. Indeed, the energy of the absorbed photon depends on the energy separation between the two states. However, this is not true at high electronic density, as it can happen in the condensed matter and in particular in semiconductor quantum structures. The Quantum Physics and Devices (QUAD) team at MPQ laboratory (CNRS/Univ. Paris Diderot), in collaboration with ELPHYSE team at LPN (...)
Carbon is an abundant element on earth, what makes it particularly appealing for applications. Unfortunately, its use in magnetism and spintronics looked difficult so far because it is intrinsically non magnetic. Researchers of the laboratory ’Quantum Materials and Phenomena’ and ’Physics and Chemistry of Surfaces and Interfaces’ have just shown that the famous C60 molecule can become magnetic when in contact with a magnetic electrode. Beyond the technical challenge, this discovery shows (...)
The laboratory Matériaux et Phénomènes Quantiques wishes you a great year 2012 !
Ultrashort pulses of terahertz frequency radiation can now be generated by semiconductor lasers. This is what a team of physicists has demonstrated using quantum cascade lasers, an electrically pumped semiconductor light source based on multi-quantum wells. By modulating the injected current of a terahertz quantum cascade laser the researchers have shown that it is possible to add up coherently the Fabry-Perot modes oscillating in the laser cavity, a technique known as active mode-locking. (...)
The first issue of MPQ International Newsletter is available !
A selection of recent results obtained by MPQ teams is higlighted
Articles presented in this first issue :
Magnetic stability of core-shell nanoparticles
Magnetoelectric coupling in multiferroic materials
Shape and order in CoPt nanoparticles
Theory of far-from-equilibrium quantum transport through a single impurity
Composite excitations of a cavity-embedded two- dimensional electron gas
A printed version is availbale on (...)
Chemically ordered bimetallic nanoparticles (Fig. a) are promising candidates for magnetic storage applications. However, the use of sub-10 nm nanomagnets requires further study of possible size effects on their physical properties. The Me-ANS group from the Materials and Quantum Phenomena Laboratory (University Paris 7 - CNRS), in collaboration with the Microstructural Investigation Laboratory (ONERA - CNRS), the Interdisciplinary Center of Nanosciences at Marseille (CINaM - CNRS) and the (...)
The fast increase in the data storage of hard disk drives and magnetic memories needs smaller and smaller magnets. A crucial issue in this miniaturization process is the growing influence of the temperature on the devices. For example, the magnetization of a nanoparticle can spontaneously switch at room temperature, loosing the stored memory. A collaboration between physicists of the laboratory ‘Matériaux et Phénomènes Quantiques’ of the Paris Diderot University and the ‘Laboratoire de Physique (...)
Single wall carbon nanotubes are currently the focus of intense research efforts in particular for their potential in the building of future electronic devices. The atomic structure of these tubes with nanometer-scale diameter can be seen as the rolling up of a graphene sheet, made only of carbon atoms. Depending on the angle chosen for rolling, the resulting nanotube can be metallic or semiconducting. Because of this link between atomic and electronic structure, the nanotubes are (...)
Doubling the quantum vacuum of a superconductor resonator
Is it possible to have two different quantum electrodynamical vacua (ground states) with the same energy in a solid-state chip ? Is such a vacuum ‘degeneracy’ robust with respect to fluctuations of the circuit parameters ? In a PRL paper by P. Nataf and C. Ciuti, it shown that these fascinating vacuum properties are indeed possible in a superconducting transmission line resonator embedding a chain of N artificial ‘fluxonium’ atoms (...)
The group Théorie of MPQ in collaboration with the experimental group Optique Quantique at LKB has published a Nature Physics paper on polariton superfluidity.
This work shows a direct demonstration of non-equilibrium superfluidity of light propagation. The transition from a normal to a superfluid regime is quantitatively described by a generalized Gross-Pitaevski theory.
Contact: Cristiano (...)
How fast can light and matter be made to interact? ’Almost instantaneously’ is the answer provided in the latest study of semiconductor structures embedded in an optical microcavity : Sub-cycle switch-on of ultrastrong light–matter interaction, Nature 458, 178-181 (12 March 2009), accompanied by a News and Views article, and by an editorial summary.
This work is the result of a collaboration between the group of ultrafast spectroscopy Terahertz spectroscopie in Konstanz (Germany), two groups (...)
Paper from the QUAD team to appear in Nature Photonics (july 2007) :
In a GaAs crystal, due to the anomalous dispersion introduced by optical phonon absorption, a phase-matched interaction is possible between a near-infrared beam and a terahertz (THz) wave. We exploit this nonlinear optical process to allow the merging of THz quantum cascade (QC) laser and telecom technologies by injecting a telecom beam into a suitably designed THz QC laser. Within the optical cavity, the phase and (...)
Picture of a cloud of laser-cooled Sr+ ions stored in a linear Paul trap.
The moving started in 2006 december. The building "Condorcet" holds by the Seine on the new campus of University Paris-Diderot in the "Paris Rive Gauche" site located on the east end of Paris.
To be noted
Discover the "Matériaux et Phénomènes Quantiques" Laboratory Film director: A. Monclin, 2009 —