title: Wave-front phase measurements of high-order harmonic beams by use of point-diffraction interferometry.
abstract: We report the wave-front phase measurement of high-order harmonics employing point-diffraction interferometry. The high-order harmonics generated in a gas-filled hollow tube showed excellent spatial coherence over nearly the whole cross section of the harmonic beams. Using this coherent harmonic source in the extreme-ultraviolet-soft-x-ray region, we have demonstrated the operation of a point-diffraction interferometer and measured the wave-front phase of high-order harmonics.
authors.affiliation: Department of Physics, Coherent X-Ray Research Center, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Korea. donggun@mail.kaist.ac.kr
authors.forename: D G
authors.initials: DG
authors.lastname: Lee
authors.forename: J J
authors.initials: JJ
authors.lastname: Park
authors.forename: J H
authors.initials: JH
authors.lastname: Sung
authors.forename: C H
authors.initials: CH
authors.lastname: Nam