Spatiotemporal characterization of single-order high harmonic pulses from time-compensated toroidal-grating monochromator.

Extreme ultraviolet (XUV) single-order high harmonic pulses with 10(6) photons/pulse were separated from multiple harmonic orders by a time-compensated toroidal-grating monochromator consisting of a pair of toroidal gratings. The first grating separates the harmonic order and the second one compensates for the pulse-front tilt. The center photon energies were tunable between 42 and 23 eV. The separated single harmonic pulses were spatially and temporally characterized as having a spot size of 58 +/- 3 microm at the focus, with a shortest pulse duration of 47 +/- 2 fs. The developed XUV light source is versatile for application to time- and space-resolved spectroscopy.