XUV Laser and method

The method of generating XUV radiation which comprises exciting alkali metal atoms or ions of the isoelectronic sequence to a storage level which is metastable against both autoionization and radiation, pumping by irradiating with a laser the excited atoms to a higher level which is metastable against autoionization but is strongly radiatively allowed to lase to a lower level other than ground and simultaneously emptying said lower level, both radiatively and by photoionization into the continua or to a level near enough to the continua, that electrons complete the emptying process.