Sensing Sub-10 nm Wide Perturbations in Background Nanopatterns Using Optical Pseudoelectrodynamics Microscopy (OPEM).

Using light as a probe to investigate perturbations with deep subwavelength dimensions in large-scale wafers is challenging because of the diffraction limit and the weak Rayleigh scattering. In this Letter, we report on a nondestructive noninterference far-field imaging method, which is built upon electrodynamic principles (mechanical work and force) of the light-matter interaction, rather than the intrinsic properties of light. We demonstrate sensing of nanoscale perturbations with sub-10 nm features in semiconductor nanopatterns. This framework is implemented using a visible-light bright-field microscope with a broadband source and a through-focus scanning apparatus. This work creates a new paradigm for exploring light-matter interactions at the nanoscale using microscopy that can potentially be extended to many other problems, for example, bioimaging, material analysis, and nanometrology.