Generation and Application of Coherent Radiation in the Water Window

Coherent extreme ultraviolet radiation around the water window region (∼4.4 nm) is generated by using an infrared driving pulses at 1400 nm, with energy 2.5 mJ and duration 40 fs in a semi-infinitive helium gas cell. The beam profile and spatial coherence characteristics of the source in this region are shown to be excellent, enabling this source to be used for coherent diffractive imaging.