Nonlinear compression has become an obligatory technique along with the development of ultrafast lasers in generating ultrashort pulses with narrow pulse widths and high peak power. In particular, techniques of nonlinear compression have experienced a rapid progress as ytterbium (Yb)-doped lasers with pulse widths in the range from hundreds of femtoseconds to a few picoseconds have become mainstream laser tools for both scientific and industrial applications. Here, we report a simple and stable nonlinear pulse compression technique with high efficiency through cascaded filamentation in air followed by dispersion compensation. Pulses at a center wavelength of 1040 nm with millijoule pulse energy and 160 fs pulse width from a high-power Yb:CaAlGdO4 regenerative amplifier are compressed to 32 fs, with only 2.4% loss from the filamentation process. The compressed pulse has a stable output power with a root-mean-square variation of 0.2% over 1 hour.

This paper describes initial experimental results from an extreme ultraviolet (EUV) radiation-pulsed atom probe microscope. Femtosecond-pulsed coherent EUV radiation of 29.6 nm wavelength (41.85 eV photon energy), obtained through high harmonic generation in an Ar-filled hollow capillary waveguide, successfully triggered controlled field ion emission from the apex of amorphous SiO2 specimens. The calculated composition is stoichiometric within the error of the measurement and effectively invariant of the specimen base temperature in the range of 25 K to 150 K. Photon energies available in the EUV band are significantly higher than those currently used in the state-of-the-art near-ultraviolet laser-pulsed atom probe, which enables the possibility of additional ionization and desorption pathways. Pulsed coherent EUV light is a new and potential alternative to near-ultraviolet radiation for atom probe tomography.

We present the temporal and spatial characterization of X-ray sources (at ~1 keV) driven by a 200 TW, 30 fs, 800 nm laser pulse on SILEX-I laser facility at Research Center of Laser Fusion. For laser copper foil interaction with laser intensity between 6 × 1018 W/cm2 and 3 × 1019 W/cm2, the X-ray images show cone-like jet structures. While the yield of X-rays is strongly dependent on the laser intensity, the plasma expansion length is weakly dependent on the laser intensity, and the open angle of the cone-like jet is not correlated to the laser intensity. The formation of the jet structure is attributed to the plasma transverse confine by the self-induced quasi-static magnetic field. An X-ray pedestal 4 ns preceding the main pulse was observed. The correlation between X-ray pedestal and collimated proton beam generation was found.