Tailoring plasmonic field within two-color laser using metallic nanostructure for the generation of high harmonics

We have proposed a metallic dipole-ellipsoid-bagel nanostructure for the generation of high harmonics via two-color laser field. Comparing with the case of the one-color field, this nanostructure enables a broader bandwidth and smoother harmonic spectra under the condition of the two-color incidence field, which is in favor of the generation of extreme-ultraviolet (XUV) radiation and isolated attosecond pulses. Numerical techniques are employed to optimize nanoantennas and attain enhanced plasmonic field. The electromagnetic properties of this nanostructure is fully analyzed and discussed. The nanostructure support the highest enhancement fact of 2500 for both of 800-nm and 1500-nm incidence, and effectively enhance the field intensity exceed 10(3) in the volumn of 50x50x50 nm(3). This nanostructure would benefit for the generation of high-harmonic, extreme-ultraviolet (XUV) radiation via plasmonic enhanced filed in a two-color multi-cycle laser field. This work would have potential application in the ultra-sensitive color sensor and the source of isolated attosecond pulses via multicycle laser.