Third harmonic spectroscopy of complex plasmonic Fano structures

For the design of optical materials with desired functionality and optical response, we require a deep understanding of their light-matter interaction. In particular, metal nano structure s have shown great potential for tailoring the linear as well as the nonlinear optical response. To gain insight into the nonlinear optical processes that occur upon illumination of metal nanoparticles with strong light fields, we perform third harmonic spectroscopy of different complex plasmonic nanoantenna arrays using widely tunable sub-30 fs laser pulses, see Fig. la.