Near-field sounding of multilayered media

A method of the coherent near-field sounding of layers' parameters of a multilayered dielectric is proposed. It is based on the field measurements with the use of subwavelength probes (emitting and receiving) that are spaced above the upper layer of the studied structure. It makes possible to achieve a subwavelength resolution at the control of the layers' depth. The developed approach can be used, for instance, for the monitoring of epitaxy of multilayered heterostructures using SNOM techniques.