Abstract: The invention related to devices and methods wherein the conditions, under which surface plasmon resonance is established, are modified by altering the balance between orientations of the spins of charge carriers in an SPR layer. The embodiments of this invention may be used as logical gates, optical filters and absorbers, optoelectronic mixers, and tunable surface plasmon sensors.

Abstract: An optical fiber surface plasmon resonance (SPR) sensor includes both a metal layer and an overlay or underlay material on its surface. Existing fiber based SPR devices are inherently incapable of monitoring aqueous systems which have a refractive index ranging between 1.33 and 1.35, and existing prism based SPR sensors have proved too cumbersome for online chemical and biochemical analyses. Inclusion of the overlay or underlay material on the SPR sensor allows monitoring media with a refractive index from 1.00 to the 1.39 barrier and above. Hence, the SPR sensor allows monitoring important biochemical and chemical aqueous processes where the media typically have a refractive index between 1.33 and 1.35. In operation, samples are simply applied to the sensing region of the SPR sensor where the metal layer and overlay or underlay materials are coated, introducing a polarized beam of light into the optical fiber, and detecting surface plasmon resonance.