RESUMO
Investigations of emission of harmonics from argon gas jet irradiated by 700 fs, 5 mJ pulses from a KrF laser are presented. Harmonics conversion was optimized by varying the experimental geometry and the nozzle size. For the collection of the harmonic radiation silicon and solar-blind diamond semiconductor detectors equipped with charge preamplifiers were applied. The possibility of using a single-crystal CVD diamond detector for separate measurement of the 3rd harmonic in the presence of a strong pumping radiation was explored. Our experiments show that the earlier suggested 0.7% conversion efficiency can really be obtained, but only in the case when phase matching is optimized with an elongated gas target length corresponding to the length of coherence.
RESUMO
Projectile time-of-flight spectra and the number of emitted electrons have been determined in coincidence for grazing scattering of slow (0.45 keV/u) multiply charged Ar ions from an atomically clean and flat LiF(001) surface. By relating projectile energy loss to kinetic electron emission we were able to determine contributions from potential electron emission even in the presence of a considerable number of kinetically excited electrons. Our results suggest a practically complete use of the available potential energy for electron emission during grazing scattering in sharp contrast to findings for the normal incidence case.
