High-harmonic generation in H2O.

We demonstrate high-harmonic generation in H(2)O using 800 and 1300 nm laser pulses up to a maximum intensity of 5x10(14) W/cm(2). Under optimal phase-matching conditions, photon energies up to approximately 60 and approximately 87 eV are produced by using 800 and 1300 nm light, respectively. The harmonic spectra in H(2)O, when compared with Xe with a similar ionization potential, exhibit significant extension of the cutoff region, indicating suppression of ionization arising from molecular orbital symmetry.