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.
© 2003 Optical Society of America
(030.1670) Coherence and statistical optics : Coherent optical effects
(120.5050) Instrumentation, measurement, and metrology : Phase measurement
(260.3160) Physical optics : Interference
(260.7200) Physical optics : Ultraviolet, extreme
(340.7450) X-ray optics : X-ray interferometry
D. G. Lee, J. J. Park, J. H. Sung, and C. H. Nam, "Wave-front phase measurements of high-order harmonic beams by use of point-diffraction interferometry," Opt. Lett. 28, 480-482 (2003)