New achievements in orbital angular momentum beam characterization using a Hartmann wavefront sensor and the Kirkpatrick-Baez active optical system KAOS.

Advances in physics have been significantly driven by state-of-the-art technology, and in photonics and X-ray science this calls for the ability to manipulate the characteristics of optical beams. Orbital angular momentum (OAM) beams hold substantial promise in various domains such as ultra-high-capacity optical communication, rotating body detection, optical tweezers, laser processing, super-resolution imaging etc. Hence, the advancement of OAM beam-generation technology and the enhancement of its technical proficiency and characterization capabilities are of paramount importance.

Light-Induced Magnetization at the Nanoscale.

Triggering and switching magnetic moments is of key importance for applications ranging from spintronics to quantum information. A noninvasive ultrafast control at the nanoscale is, however, an open challenge. Here, we propose a novel laser-based scheme for generating atomic-scale charge current loops within femtoseconds.

Ultra-Fast-VUV Photoemission Study of UV Excited 2-Nitrophenol.

The initial deactivation pathways of gaseous 2-nitrophenol excited at 268 nm were investigated by time-resolved photoelectron spectroscopy (TRPES) with femtosecond-VUV light, produced by a monochromatized high harmonic generation source. TRPES allowed us to obtain new, valuable experimental information about the ultrafast excited-state dynamics of 2-nitrophenol in the gas phase. In accord with recent ab initio on-the-fly nonadiabatic molecular dynamic simulations, our results validate the occurrence of an ultrafast intersystem crossing leading to an intermediate state that decays on a subpicosecond time scale with a branched mechanisms.

Giant magneto-electric coupling in 100 nm thick Co capped by ZnO nanorods.

Here we report a giant, completely reversible magneto-electric coupling of 100 nm polycrystalline Co layer in contact with ZnO nanorods. When the sample is under an applied bias of ±2 V, the Co magnetic coercivity is reduced by a factor 5 from the un-poled case, with additionally a reduction of total magnetic moment in Co. Taking into account the chemical properties of ZnO nanorods measured by X-rays absorption near edge spectroscopy under bias, we conclude that these macroscopic effects on the magnetic response of the Co layer are due to the microstructure and the strong strain-driven magneto-electric coupling induced by the ZnO nanorods, whose nanostructuration maximizes the piezoelectric response under bias.

Tunable orbital angular momentum in high-harmonic generation.

Optical vortices are currently one of the most intensively studied topics in optics. These light beams, which carry orbital angular momentum (OAM), have been successfully utilized in the visible and infrared in a wide variety of applications. Moving to shorter wavelengths may open up completely new research directions in the areas of optical physics and material characterization.