Magneto-Optical Device Based on Polarization Sensitivity for Perspective Biosensing Applications

Electromagnetic wave propagation in a structure comprising a magneto-optical layer placed on the top of a photonic crystal is theoretically studied. It is shown that the maximal rotation of the reflected wave polarization (Kerr-Faraday rotation) is achieved when wave vectors of TE and TM modes of the demagnetized structure are equal. The analysis of polarization ellipse-the Kerr-Faraday rotation angle-with respect to small changes of the dielectric permittivity of a medium adjoined to the magneto-optical layer demonstrated a high sensitivity of 25000 degrees/RIU. We thus propose a novel design of perspective sensing elements for biosensing and chemical sensing.