Molecular high harmonic generation in a two-color field.

We experimentally investigate the high harmonic generation (HHG) from CH4 molecules and Xe atoms in a two-color field (using the 800 nm laser and the tunable laser with the longer wavelength from 1500 nm to 1900 nm), and observe that the longer wavelength component can destructively suppress the HHG from CH4 molecules. By controlling the time delay between the two color laser pulses or tuning the laser intensity of the longer wavelength component, the suppressions of the HHG from CH4 molecules and the enhancements of the HHG from Xe atoms at the same laser condition are observed. The results indicate that the longer wavelength component around the molecular infrared absorption can suppress the molecular HHG process.