Efficient supercontinuum generation by UV-assisted midinfrared plasmonic fields

We theoretically investigate high-order harmonic generation in UV-assisted midinfrared plasmonic fields. It is found that the quantum paths contributing to the harmonics can be dramatically enhanced by adding a femtosecond UV pulse, which permits high efficient harmonic radiation under relatively low driving intensity condition and thus potentially avoids thermal damage of nanosystems. We present discussions on the influence of UV pulse parameters, including the delay, pulse duration, wavelength, and intensity, to demonstrate the prediction. Our results also show that the UV pulse, acting as a temporal trigger, in combination with the spatial inhomogeneity effect of the midinfrared plasmonic field, is robust for broadband supercontinuum generation, and this process is general and not limited to a certain driving pulse duration, inhomogeneous distribution form, and carrier-envelope phase of the midinfrared electric field.