Polarimetric measurement of optically perturbed surface plasmonic field

Abstract

A surface plasmon (SP) field excited at the metal–air interface by a TM-polarized laser and perturbed by an unpolarized, weakly absorbing laser beam leads to an understanding of the SP decay field’s contribution to specular reflection at the near field. The locally perturbed near field results in a spatial variation of the magnitude of the SP decay field due to the photo-thermal effect on the excited SP wave. The SP decay field of different magnitude interferes with the specular reflected field, affecting its polarization and phase characteristics. The changes in the resulting far field are polarimetrically analyzed to extract the polarization ellipse parameters and the phase changes in the entire plasmonic field region. The obtained results are promising for potential applications in all-optical polarization modulators and switches for optical computing.