Enhanced VUV-assisted high harmonic generation

We have enhanced extreme ultraviolet (XUV) harmonics around 90 eV in He using a combination of vacuum ultraviolet harmonics, generated in a Xe capillary, and the strong infrared (IR) laser pulse. With no changes in the IR input energy or the configuration of the He target, the collinearly focused combination of the two fields changed the spectral properties and increased the yield of the XUV harmonics compared to those generated with the IR field alone.