Nanoantenna enhanced optical nonlinearity of lithium niobate nanoparticles for the coherent excitation of nanoantenna arrays

In this project we want to combine optical nanoantennas and nonlinear optical nanoparticles to obtain tailored nonlinear optical elements at the nanoscale. The nanoantenna arrays will be fabricated by electron beam lithography on a fused silica substrate and will have the shape of a small rod or triangle. These metal nanoantennas allow focusing of laser light into deep sub-wavelength volumes. In a second electron beam lithography step we then want to incorporate nonlinear optical materials, such as lithium niobate nanoparticles, directly into the hotspots of the nanoantennas. The high light intensities will induce nonlinear optical effects in the nanoparticles (see Fig. 1). The project will combine the know-how of the University of Stuttgart in nanofabrication with the expertise from Freiburg in nonlinear optical nanoparticles. Eventually, we want to use the nonlinear nanoparticles as emitters for the coherent excitation of the nanoantenna arrays and demonstrate a first phased array at the nanoscale.

Fig.1: Enhancement of the conversion efficiency of nonlinear optical effects in lithium niobate nanoparticles using a resonant plasmonic nanoantenna: A local coherent light source at the second harmonic.