Publications de Taofiq Paraïso

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The present Ph.D. thesis consists in a series of experiments carried out in the Laboratory of Quantum Optoelectronics under the direction of professor Benoît Deveaud-Plédran between April 2006 and April 2010. We study the effect of lateral confinement on t ...

Non-linear interactions in coherent gases are not only at the origin of bright and dark solitons and superfluids; they also give rise to phenomena such as multistability, which hold great promise for the development of advanced photonic and spintronic devi ...

We demonstrate three-dimensional spatial confinement of exciton-polaritons in a semiconductor microcavity. Polaritons are confined within a micron-sized region of slightly larger cavity thickness, called mesa, through lateral trapping of their photon compo ...

In this work, we study the influence of the excitation conditions on power-dependent spin switching and spin multistability of exciton polaritons in planar semiconductor microcavities. We obtain experimental evidence for the influence of a reservoir of non ...

We experimentally investigate the relaxation of spatially confined microcavity polaritons. We measure the time- and energy-resolved photoluminescence under resonant excitation and in the low-density regime. In this way, we have access to the time evolution ...

Coherent manipulation of spin ensembles is a key issue in the development of spintronics. In particular, multivalued spin switching may lead to new schemes of logic gating and memories. This phenomenon has been studied with atom vapours 30 years ago, but is still awaited in the solid state. Here, we demonstrate spin multistability with microcavity polaritons in a trap. Owing to the spinor nature of these light-matter quasiparticles and to the anisotropy of their interactions, we can optically control the sp

We present the optical tomography of the probability density of microcavity polaritons, confined in three dimensions by cylindrical traps of various sizes. Collecting the photoluminescence emitted by the quasimodes under continuous nonresonant laser excita ...

Control of the wave function of confined microcavity polaritons is demonstrated experimentally and theoretically by means of tailored resonant optical excitation. Three dimensional confinement is achieved by etching mesas on top of the microcavity spacer l ...

We study the emission properties of confined polariton states in shallow zero-dimensional traps under nonresonant excitation. We evidence several relaxation regimes. For slightly negative photon-exciton detuning, we observe a nonlinear increase of the emis ...

We report on the dynamics of confined zero-dimensional polaritons. We excite resonantly discrete polariton states optically with a tailored picosecond laser pulse and observe their emission time resolved in the two-dimensional k space or real space. We are ...

We experimentally demonstrate a technique for the generation of optical beams carrying orbital angular momentum using a planar semiconductor microcavity. Despite being isotropic systems with no structural gyrotropy, semiconductor microcavities, because of ...

In this work, we report on the first realization of multi-valued spin switching in the solid-state. We investigate the physics of spinor bistability with microcavity polaritons in a trap. Spinor interactions lead to special bistability regimes with decoupled thresholds for spin-up and spin-down polaritons. This allows us to establish state-of-the-art spin switching operations. We evidence polarization hysteresis and determine appropriate conditions to achieve spin multistability. For a given excitation cond

We present the optical tomography of the probability density of quasiparticles, the microcavity polaritons, confined in three dimensions by cylindrical traps. Collecting the photoluminescence emitted by the quasimodes under continuous nonresonant laser exc ...

We performed studies on microcavity polaritons trapped along the three dimensions of space, under resonant excitation on a confined lower polariton state. We observed various nonlinear behaviors as a function of the pump power, without any apparent loss of ...

Taofiq Paraïso

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Dynamics of Interactions of Confined Microcavity Polaritons

Ultrafast tristable spin memory of a coherent polariton gas

Engineering the spatial confinement of exciton polaritons in semiconductors

Influence of a nonradiative reservoir on polariton spin multistability

Enhancement of microcavity polariton relaxation under confinement

Multistability of a coherent spin ensemble in a semiconductor microcavity

Probability density tomography of microcavity polaritons confined in cylindrical traps of various sizes

Coherent optical control of the wave function of zero dimensional exciton polaritons

Nonlinear relaxation of zero-dimension-trapped microcavity polaritons

Spatial dynamics of confined semiconductor microcavity polaritons

Spin-to-orbital angular momentum conversion in semiconductor microcavities

Multi-Valued Spin Switch in a Semiconductor Microcavity

Probability density optical tomography of confined quasiparticles in a semiconductor microcavity

Resonant nonlinear studies of trapped 0D-microcavity polaritons

Optical Tomography Of Confined Microcavity Polariton Probability Densities

Collisional Relaxation And Oscillation Damping In A Trapped Polariton Gas

Time Evolution Of The Wave Function Of 0D Polaritons In The Momentum Space