29 research outputs found
Stochastic precession of the polarization in a polariton laser
Microcavity polaritons in the lasing regime undergo a spontaneous symmetry
breaking transition resulting in coherent emission with a well defined
polarization. The order parameter is thus a vector describing both the laser
global phase and polarization. Using an ultrafast single-shot detection
technique we show that polariton lasing in GaAs-based microcavities presents a
high degree of second order coherence () above
threshold, and that the initial polarization is stochastic, taking any possible
direction in the Poincar\'e sphere (linear, elliptical or circular). Once the
polarization direction is established, subsequent oscillations of the emission
probability witness the presence of an intrinsic polarization splitting. Our
results show the negligible role of polariton interactions in the total
emission statistics and in the establishment of the initial polarization.Comment: 9 pages, 6 figure
Direct observation of Dirac cones and a flatband in a honeycomb lattice for polaritons
Two-dimensional lattices of coupled micropillars etched in a planar
semiconductor microcavity offer a workbench to engineer the band structure of
polaritons. We report experimental studies of honeycomb lattices where the
polariton low-energy dispersion is analogous to that of electrons in graphene.
Using energy-resolved photoluminescence we directly observe Dirac cones, around
which the dynamics of polaritons is described by the Dirac equation for
massless particles. At higher energies, we observe p orbital bands, one of them
with the nondispersive character of a flatband. The realization of this
structure which holds massless, massive and infinitely massive particles opens
the route towards studies of the interplay of dispersion, interactions, and
frustration in a novel and controlled environment
Preparation of boron-doped diamond nanowires and their application for sensitive electrochemical detection of tryptophan
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