Far-field Raman color superlensing based on disordered plasmonics

Plasmon multiple scattering within a disordered metal-dielectric medium allows one to enhance a cubic susceptibility drastically, and thus stimulated Raman scattering (SRS) can occur in highly confined media exposed to the continuous-wave low-powered pump. In this study, a percolated 50 nm titanium oxynitride thin film is used as a disordered nonlinear metalens that meets epsilon-near-zero (ENZ) wavelengths in the visible and near infrared region. We experimentally demonstrate a far-field Raman superlensing effect by showing a subwavelength resolution of λ/6NA at different SRS overtones using multiwalled carbon nanotubes directly dispersed on the metalens.