Nanoscattering measurement of 3D polarization and spin in a random evanescent wave

Nonparaxial random light fields, whose pointwise polarization states are generally three-dimensional (3D) in character, exhibit diverse polarimetric qualities and extraordinary spin properties. In this work, we employ a nanoparticle as a local probe scatterer and demonstrate a measurement of the recently introduced notions of polarimetric dimension and degree of nonregularity as well as the related spin structure in a random quasimonochromatic evanescent wave. The results in part confirm the theoretical prediction [ Opt. Lett. 44 , 215 ( 2019 ) OPLEDP 0146-9592 10.1364/OL.44.000215 ] that the evanescent waves of a specific common type are generally in a 3D nonregular polarization state.