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We present a generalized differential image motion monitor (GDIMM). It is a compact instrument dedicated to the measurement of four parameters of optical turbulence: seeing, isoplanatic angle, coherence time and wavefront coherence outer scale. The GDIMM is based on a small telescope (28 cm diameter) equipped with a three-hole mask at its entrance pupil. The instrument is fully automatic, and performs continuous monitoring of turbulence parameters at the Calern Observatory (France). This paper gives a description of the instrument, data processing and error budget. We also present statistics of three and a half years of monitoring of turbulence parameters above the Calern Observatory. [ABSTRACT FROM AUTHOR]

The interplay between the superradiant emission of a cloud of cold two-level atoms and the radiation pressure force is discussed. Using a microscopic model of coupled atomic dipoles driven by an external laser, the radiation field and the average radiation pressure force are derived. A relation between the far-field scattered intensity and the force is derived, using the optical theorem. Finally, the scaling of the sample scattering cross-section with the parameters of the system is studied. [ABSTRACT FROM AUTHOR]

Downlink measurement campaigns from the optical downlink terminal OSIRISv1 onboard the LEO satellite Flying Laptop were carried out with the French Observatoire de la Côte d'Azur and with two Optical Ground Stations of the German Aerospace Center. On/off keyed data at 39 Mb/s were modulated on the laser signal, and according telecom reception was performed by the ground stations. The pointing of the laser terminal was achieved by open-loop body pointing of the satellite orientation, with its star sensor as attitude control signal. We report here on the measurements and investigations of the downlink signal and the data transmission.

The future generation of extremely large telescopes will be certainly equipped with wide-field adaptive optics systems. All the components of such adaptive optics systems have to be precisely specified, and most of the technical specifications are related to atmospheric turbulence parameters, particularly the profile of the refractive index structure constant C n 2( h ). The monitor Profiler of Moon Limb (PML) for the extraction of the C n 2( h ) profile with high vertical resolution for nighttime and daytime conditions by the observation of the moon limb or sun edge has been developed and is now routinely exploited at the Calern Observatory on the French Riviera. The PML instrument uses a differential method with two small subapertures through which the moon limb or sun edge are observed, leading to a continuum of double stars that allows a scan of the whole atmosphere with high resolution in altitude. The PML is an autonomous instrument aided by a set of equipment such as an all-sky camera, a small meteorological station, and an automatic system to cover the two subapertures with solar filters to switch from night/moon to day/solar observations. In addition, the PML instrument provides in real time a large characterization of the atmospheric turbulence since it can measure other turbulence parameters, such as the total seeing and the isoplanatic angle.

Optical system performances can be affected by local optical turbulence created by its surrounding environment (telescope dome, clean room, or atmospheric layer). This paper follows a previous one introducing the INdoor TurbulENce SEnsor (INTENSE) instrument for optical turbulence characterization in a local area by exploitation of laser beam angle-of-arrival fluctuations. After a brief summary of the theoretical background, we present in this part results obtained using the INTENSE instrument in various optical integration testing clean rooms and telescope domes, each with specific air behavior conditions.

Optical system performances can be affected by local optical turbulence created by its surrounding environment (telescope dome, clean room, atmospheric surface layer). We present our new instrument INdoor TurbulENce SEnsor (INTENSE) dedicated to this local optical turbulence characterization. INTENSE consists of using several parallel laser beams separated by non-redundant baselines between 0.05 and 2.5 m and measuring the angle of arrival fluctuations from spot displacements on a CCD. After introducing the theoretical background, we give a description of the instrument including a detailed characterization of instrumental noise and, finally, give the first results for the characterization of the turbulence inside clean rooms for optical systems studies.

We realize experimentally an atom-optics quantum-chaotic system, the quasiperiodic kicked rotor, which is equivalent to a 3D disordered system that allows us to demonstrate the Anderson metal-insulator transition. Sensitive measurements of the atomic wave function and the use of finite-size scaling techniques make it possible to extract both the critical parameters and the critical exponent of the transition, the latter being in good agreement with the value obtained in numerical simulations of the 3D Anderson model.

We study the destruction of dynamical localization experimentally observed in an atomic realization of the kicked rotor by a deterministic Hamiltonian perturbation, with a temporal periodicity incommensurate with the principal driving. We show that the destruction is gradual, with well-defined scaling laws for the various classical and quantum parameters, in sharp contrast to predictions based on the analogy with Anderson localization.

Dynamical localization is a localization phenomenon taking place, for example, in the quantum periodically driven kicked rotor. It is due to subtle quantum destructive interferences and is thus of intrinsic quantum origin. It has been shown that deviation from strict periodicity in the driving rapidly destroys dynamical localization. We report experimental results showing that this destruction is partially reversible when the deterministic perturbation that destroyed it is slowly reversed. We also provide an explanation for the partial character of the reversibility.