Concurrent polarization retrieval Method in multi- heterodyne scanning near-field optical Microscopy

Scanning near-field optical microscopy (SNOM) is a popular tool to overcome the diffraction limit for the investigation of subwavelength-scale optical structures. For nearly 30 years, various configurations have been implemented to characterize the interactions of the electromagnetic field with nanostructures in the near field. An accurate understanding of these interactions requires a detailed knowledge of the field, including the state of polarization (SOP) in the near field. The state of polarization is easily accessible in far-field microscopy, but is challenging to measure in the near field. When the SNOM probe interacts with the near field and scatters the signal to the far field, the near-field polarization may be considerably altered. Moreover, the near-field polarization may be oriented in all three dimensions whereas far-field propagation implies a two-dimensional (transverse) polarization.