Nonlinear optical absorption in the AgO_x-type super-resolution near-field structure

Nonlinear optical absorption in the AgO_x-type super-resolution near-field structure [glass/ZnS-SiO₂ (170 nm)/AgO_x (15 nm)/ZnS-SiO₂ (40 nm)] was investigated using a confocal Z-scan technique with a continuous He-Ne laser. The transmittance Z-scan shows that the sample undergoes a phase transition with increasing incident laser power. The phase transition of the sample with higher incident laser power is due to permanent local structure damage caused by the laser heating process.