SOFT X-RAY LASER IN LOW-CHARGED NITROGEN IONS BY OPTICAL-FIELD-INDUCED IONIZATION

摘要

The 45.2-nm x-ray lasing to the ground state in low-charged nitrogen ions (NIII 3s(~2S)-2p(~2P)) was successfully demonstrated at a commercial TW femtosecond laser system by optical-field ionization for the first time. A small signal gain coefficient of 9.6 cm~(-1) and a gain-length product of 3.84 for the NIII 3s(~2S)-2p(~2P) transition x-ray laser were measured for an only 25-mJ linearly-polarized 100-fs pump laser pulse.