Interferometric near-field apparatus based on multi-pole sensing

摘要

An apparatus suitable for providing near-field measurements of a workpiece. The apparatus comprises a source of electromagnetic radiation for generating an incident wave; means for directing at least a portion of the incident wave to the workpiece; a probe tip acting as an antenna and capable of re-radiating a signal wave, said signal wave developing as an interactive coupling between said workpiece and said probe tip; means for creating an interference signal based on the signal wave and a reference wave; and a detector for interrogating at least one of the phase and amplitude of the interference signal.