Applications of high-repetition-rate tabletop soft x-ray laser: laserablation with a focused beam and reflectometry of materials,

摘要

Abstract: We report the first applications of a soft x-ray laser in materials processing and diagnostics. We have focused a Ne- like Ar capillary discharge laser ($lambda $EQ 46.9 nm) operating at a repetition rate of 1 Hz using a spherical Si/Sc multilayer coated mirror. The energy density obtained significantly exceeded the threshold for the ablation of metals. Ablation of stainless steel, aluminum and brass samples is reported. The laser ablation patterns on brass were used in combination with ray tracing computations to characterize the focused beam. The radiation intensity within the 2 $mu@m central region of the focal spot is estimated to be $CNGR 10$+11$/ W/cm$+2$/, with a corresponding energy density of $CNGR 100J/cm$+2$/. In a separate experiment we have conducted laser reflectometry measurements for a number of different samples. These measurements resulted in the characterization of the reflectivity of Si/Sc multilayer mirrors as a function of angle and in the determination of optical constants for Si, GaP, InP, GaAs, GaAsP and Ir. The measurements of InP and GaAsP resulted in the first experimental values to our knowledge for these materials at this wavelength.!9