New instrumentation has been developed that is dedicated to the measurement of surface morphology with high resolutions and short acquisition times. Sinusoidal phase-shifting interferometry is demonstrated to provide within an acquisition time of only a few milliseconds topographic images with ~1 nm height precision, ~1 μm lateral resolution, and a few tens of pm sensitivity. A white-light scanning microscope is also under development, using an in-house developed high speed, intelligent CCD camera, the first tests of which demonstrate the feasibility of providing topographic images of deep surface relief (several microns to several tens of microns) within less than 0.3 s. The useful lateral field of view can be extended by employing image “stitching” while maintaining a high lateral resolution. 


Femtosecond modelocked lasers using new ytterbium-doped borate crystals (Yb:Sr3Y(BO3)3, Yb:Ca4GdO(BO3)3 and Yb:Ca4YO(BO3)3) are demonstrated. Pulse duration as short as 69 fs has been obtained. To modelock such lasers, fast saturable absorbers need to be used. Two different types of fast saturable absorbers have been studied: low-temperature-grown semiconductor mirrors (SESAM) and high-energy-ion-implanted semiconductor Bragg reflectors (SBR). We demonstrated, for the first time to our knowledge, that ion-implanted SBR can be used to modelock oscillators using Yb-doped materials.

We describe the Teramobile system, a new mobile femtosecond multi-terawatt laser and detection system based on a state-of-the art CPA laser system embedded in a standard freight container, as well as a mobile detection unit allowing a characterization of the nonlinear propagation of high power laser pulses over long horizontal distances. The unique mobility feature of the whole system opens the way to previously unreachable applications for high-power laser pulses in the field of atmospheric research (lidar, laser-triggered lightning), which are also briefly reviewed.

Commercial grating-tuned single-mode extended-cavity semiconductor lasers (ECLD's) can be tuned over 100 nm around 1.55 μm. This continuous tuning with no mode-hopping requires delicate factory adjustments and a high mechanical stability. These constrains are relaxed by the adjunction of a photorefractive crystal inside the cavity which creates an adaptive spectral filter which decreases the loss of the lasing-mode and thus enhances its stability.

In this article we report a new wavefront sensor, developed at the Laboratoire de Spectroscopie Atomique et Ionique, for a full characterization of soft X-ray beams. The Shack-Hartmann sensor has a theoretical accuracy in the order of $\lambda/100$ at a wavelength around 13 nm. A cartography of the wave-vectors pointing of laser-pumped soft X-ray laser has been achieved. It has shown the presence of many ripples probably coming from plasma instabilities. Capillary discharge soft X-ray laser has been also investigated. For all the pumping configurations, the wavefront is spherical, divergent with a radius of about 6.5 m at 2.5 m from the plasma end. The best wavefront exhibits an error to a perfect wave of 3λ rms. Assuming to focus the beam with a f = 50 mm diffraction-limited mirror, a theoretical focal spot size of 0.5 μm in diameter have been estimated containing 70% of the incident energy. In that case an intensity of 4 × 1013 W cm−2 should be achieved.

In a series of experiments we explore various aspects of femtosecond pulse shaping by coherent filters engraved in a persistent spectral hole burning (PSHB) material. We have in mind the coherent control of quantum systems, with high resolution and large number of addressable spectral points. We examine the phase correction efficiency of this approach, relying on Fourier transform spectral interferometry techniques to characterize the coherent filter. Two different PSHB materials are considered, with two different setups, involving different values of repetition rate, fluence, wavelength, spectral width and pulse duration. 


A new process of microstereolithography to manufacture freeform solid three-dimensional micro-components with outer dimensions in the millimetre size range is presented. The process, based on the use of a liquid crystal display as a dynamic mask generator, works with conventional industrial UV-sensitive stereolithographic materials. The main innovation of the process consists in using the optical frequency up-conversion of images from the visible to the UV range in order to overcome the opacity of LCD's in the UV domain. 400 × 400 points up-converted images have been obtained to generate solid three-dimensional objects.

In this article we illustrate important characteristics of the diffraction of cold atoms from periodic light potentials generated from coupling a light wave to dielectric nanostructures. We apply a recently developed theoretical approach to investigate the behavior of Cs atoms dropped onto a periodically modulated optical dipole potential where the period of the modulation is controlled by the periodicity of the dielectric array. These nanostructures take the form of one-dimensional line gratings or two-dimensional point gratings. We discuss several important parameters critical to the successful realisation of laboratory experiments and future atom-optical instrumentation using this new kind of atomic diffraction medium.

To transfer and expand in the optical telecommunication range the accurate 5S1/2(F = 3) – 5D5/2 (F = 5) rubidium frequency reference at 778 nm (385.285 THz), we employ a second harmonic generation (SHG) process coupled to an optical frequency comb (OFC) both based on the use of a low power and narrow linewidth laser diode operating around 1556 nm. The Rb optical frequency reference is known with an accuracy of 2.6 × 10−12 and exhibits a frequency stability of 4 × 10−13τ−1/2, with a Flicker plateau of 2 × 10−14 for τ > 200 s. With 20 mW of laser power at 1556 nm, we perform a SHG process in a periodically poled lithium niobate (PPLN) crystal and we obtain 6.5 μW of harmonic radiation at 778 nm, used to phase lock the IR laser against a Rb optical frequency standard (OFS). This Rb-referenced fundamental radiation at 1556 nm is duplicated as 34 lines spaced by 10 GHz using an electro-optic phase modulator (EOM). This preliminary result is mainly limited by unexpected high optical losses in the Fabry Perot cavity, which comprises the EOM.