Influence of the sample-probe coupling on the resolution of transmitted near-field optical image

Numerical simulation of photon scanning tunneling microscopy is presented to study the near-field distribution in the vicinity a dielectric surface with one-dimensional sub-wavelength structures. Multiple scattering between the probe tip and the sample has been taken into account implicitly by matching electromagnetic boundary conditions at interfaces. The near-field intensity in transmission mode through two ridges on surface has been modeled in order to analyze the resolution of the system. The effects on the signal by the sample-tip coupling, the polarization of the incident light, and the angle of incidence are investigated. We find that the capability to recognize the feature will be improved when the tip–object interaction is strong.