|Spectral distribution of attosecond pulse with
(a) carbon filter and (b) carbon and boron filters.
An attosecond (10–18 s: as) pulse is shortest laser pulse in the world. We successfully generated isolated attosecond pulse with 284 eV photon energy (4.4 nm wavelength) using a driving laser with only 247 µJ pulse energy, which pulse energy is lowest value ever reported. Since the K-shell absorption edge in carbon exists in 284 eV region, the laser would be useful for visualizing of living cell structure. (Page 43)