Sensing of Surface and Bulk Refractive Index Using Magnetophotonic Crystal with Hybrid Magneto-Optical Response

Sensors. 2021. Vol. 21. No. 6. Article 1984.

Ignatyeva D., Kapralov P., Golovko P., Shilina P., Khramova A., Sekatskii S., Nur E Alam M., Alameh K., Vasiliev M., Kalish A., Belotelov V.

We propose an all-dielectric magneto-photonic crystal with a hybrid magneto-optical
response that allows for the simultaneous measurements of the surface and bulk refractive index of
the analyzed substance. The approach is based on two different spectral features of the magnetooptical
response corresponding to the resonances in p- and s-polarizations of the incident light.
Angular spectra of p-polarized light have a step-like behavior near the total internal reflection angle
which position is sensitive to the bulk refractive index. S-polarized light excites the TE-polarized
optical Tamm surface mode localized in a submicron region near the photonic crystal surface and
is sensitive to the refractive index of the near-surface analyte. We propose to measure a hybrid
magneto-optical intensity modulation of p-polarized light obtained by switching the magnetic field
between the transverse and polar configurations. The transversal component of the external magnetic
field is responsible for the magneto-optical resonance near total internal reflection conditions, and
the polar component reveals the resonance of the Tamm surface mode. Therefore, both surface- and
bulk-associated features are present in the magneto-optical spectra of the p-polarized light.

Keywords: плазмоника, optical sensors, surface plasmons, оптический сенсор, photonic crystals, фотонный кристалл