Identification of a resonant imaging process in apertureless near-field microscopy

The underlying physics of apertureless imaging in the far infrared and the identification of a mechanism that resulted from a mesoscopic resonance were analyzed. A configurational resonance of the scanning tip-surface system was identified to be the dominating mechanism that formed the image. The imaging was dominated by an ac coupling between incident light field and the tip-surface system with the use of time-resolved THz experiments. The results show that the configurational resonances dominated optical near-field imaging in the far infrared.