D. Ostling et al., THEORY OF NONLINEAR-OPTICAL PROPERTIES OF SMALL METALLIC SPHERES, Zeitschrift fur Physik. D, Atoms, molecules and clusters, 28(2), 1993, pp. 169-175
We calculate the nonlinear optical properties of small metallic sphere
s using electromagnetic theory and assuming that the local response of
the conduction electrons is the same as for a plane surface. Electrom
agnetic Mie-resonances cause a strong increase of the second and highe
r harmonics in the reflected light. Detailed results are given for the
second and third harmonic generation, its dependence on the frequency
and polarization of the incident light, and on the cluster size. An e
nhancement of the second harmonic generation by a factor of about 5000
is obtained for small spherical metallic clusters. This is in good ag
reement with experiments on artificially roughened metal surfaces.