| Abstract: | Efficient harmonic light generation can be achieved with ultrathin films
by coupling an incident pump wave to an epsilon-near-zero (ENZ) mode of
the thin film. As an example, efficient third harmonic generation from an
indium tin oxide nanofilm (.lamda./42 thick) on a glass substrate for a
pump wavelength of 1.4 .mu.m was demonstrated. A conversion efficiency of
3.3.times.10.sup.-6 was achieved by exploiting the field enhancement
properties of the ENZ mode with an enhancement factor of 200. This
nanoscale frequency conversion method is applicable to other plasmonic
materials and reststrahlen materials in proximity of the longitudinal
optical phonon frequencies. |