Dynamic Aperture of Near-Field Super Resolution Structures

Direct experimental observation of the near-field aperture formed in the super resolution near-field structure of glass/SiN(170 nm)/Sb(15 nm)/SiN(20 nm) has been achieved using a tapping-mode tuning-fork near-field scanning optical microscope. Both propagating and evanescent field intensities were found at the focused spots of the surface of the super resolution structure. Images of the near-field intensity gradients at different excited laser powers (0.45–2.33 µW) demonstrated that the area of the static evanescent intensity could be stably controlled.