Persistent Ground-State Planar Alignment of Iodine Molecule through Resonant Excitation.

We demonstrate the generation of a persistent planar molecular alignment by subjecting a relatively warm gas sample to a resonant femtosecond laser pulse. By optically probing I_{2} molecules in their vibronic ground states, we observe a persistent delocalization of their axes near the plane orthogonal to the field direction. This phenomenon is attributed to the one-photon resonant excitation, primarily removing molecules from the thermal ground-state distribution that are initially aligned along the field, i.

High-gain far-detuned nonlinear frequency conversion in a few-mode graded-index optical fiber.

We present theoretical and experimental evidence of high-gain far-detuned nonlinear frequency conversion, extending towards both the visible and the mid-infrared, in a few-mode graded-index silica fiber pumped at 1.064  , and more specifically achieving gains of hundreds of dB per meter below 0.65  and beyond 3.

Phase-matching-free ultrashort laser pulse characterization from a transient plasma lens.

A phase-matching-free ultrashort pulse retrieval based on the defocusing of a laser-induced plasma is presented. In this technique, a pump pulse ionizes a rare gas providing a plasma lens whose creation time is ultrafast. A probe pulse propagating through this gas lens experiences a switch of its divergence.

Multi-octave mid-infrared supercontinuum generation in tapered chalcogenide-glass rods.

We report on the experimental development of short-tapered chalcogenide-glass rods for mid-infrared supercontinuum generation. Multi-octave spectral broadening of femtosecond laser pulses is demonstrated from 1.6 to 15.

Discretized Conical Waves in Multimode Optical Fibers.

Multimode optical fibers are essential in bridging the gap between nonlinear optics in bulk media and single-mode fibers. The understanding of the transition between the two fields remains complex due to intermodal nonlinear processes and spatiotemporal couplings, e.g.