arXiv subjects
Publications and source records attributed to Paul Monnier.
A ground-based mobile 3D lidar observatory has been developed for simultaneous measurements of wind speed, temperature, water vapor and carbon dioxide absorption in the atmosphere. The present paper reports details of the instruments, assesses the current performances and gives some examples of measurements for different geophysical applications.
Model parametrizations in the convective boundary layer are still at work especially in the interfacial layers with the surface and the free troposphere. The present paper reports simultaneous turbulence-scale lidar observations of wind speed, temperature and specific humidity in the convective boundary layer in temperate and semi-arid regions. The collected data are used to assess new parametrizations in particular in the entrainment layer.
Multi-cavity photonic systems, known as photonic molecules (PMs), are ideal multi-well potential building blocks for advanced quantum and nonlinear optics. A key phenomenon arising in double well potentials is the spontaneous breaking of the inversion symmetry, i.e. a transition from a delocalized to two localized states in the wells, which are mirror images of each other. Although few theoretical studies have addressed mirror-symmetry breaking in micro and nanophotonic systems, no experimental evidence has been reported to date. Thanks to the potential barrier engineering implemented here, we demonstrate spontaneous mirror-symmetry breaking through a pitchfork bifurcation in a PM composed of two coupled photonic crystal nanolasers. Coexistence of localized states is shown by switching them with short pulses. This offers exciting prospects for the realization of ultra-compact, integrated, scalable optical flip-flops based on spontaneous symmetry breaking. Furthermore, we predict such transitions with few intracavity photons for future devices with strong quantum correlations.
We show that Coherent Population Oscillations effect allows to burn a narrow spectral hole (26Hz) within the homogeneous absorption line of the optical transition of an Erbium ion-doped crystal. The large dispersion of the index of refraction associated with this hole permits to achieve a group velocity as low as 2.7m/s with a ransmission of 40%. We especially benefit from the inhomogeneous absorption broadening of the ions to tune both the transmission coefficient, from 40% to 90%, and the light group velocity from 2.7m/s to 100m/s.