Nonlinear heating and scattering in a single silicon nanostructure

We recently achieved n_2 ~10-1 μm^2/mW on a single silicon Mie resonator, i.e. five orders-of-magnitude improvement of silicon nonlinearity. Here we present the direct evidence quantitatively linking the nonlinearity to temperature rise with 10K precision, and unravel that the huge optical nonlinearity is due to nonlinear temperature rise, coupled with nonlinear absorption, resulting in 1000K increase with ~10 mW/μm^2 excitation. We developed corresponding numerical simulation tools that confirm our observations and can be adapted to explain general nanostructure heating.