We review our recent results regarding the optical properties of arrays of noncentrosymmetric metal nanoparticles. The structural symmetry of the particles is easily broken by fabrication related imperfections, such as small scale defects, which gives rise to optical activity effects in the linear and second-order optical responses. Evidence of higher multipole (magnetic-dipole and electric-quadrupole) emission in second-harmonic generation is provided by comparing polarization dependent signals in the reflected and transmitted directions. The second-order response of noncentrosymmetric nanodimers with a nanogap is not driven by strong local fields in the nanogap. Instead polarization conversion of the local filed and its asymmetric distribution around the particle perimeters play the dominant role in strong second-harmonic generation. Second- and third-harmonic microscopy reveal different tensorial responses between individual nanodots.


Seminar, 10th of April, 11:00h. Conference Room
Hosted by Prof. Jordi Martorell