The role of normal polarization in far-field subwavelength imaging by a dielectric microsphere or microcylinder

The role of normal polarization in far-field subwavelength imaging granted by a dielectric microsphere or microcylinder is revealed. Two hypotheses explaining this imaging are suggested. One of these hypotheses is confirmed by exact numerical simulations. It is an efficient excitation of a set of creeping waves at a curved dielectric interface by a normally polarized dipole. After their emission from the microparticle surface these waves create a diffraction-free imaging beam, and subwavelength imaging becomes possible.