Broad band infrared modulation using spintronic-plasmonic metasurfaces

We present magnetic field induced modulation of the optical response of slit plasmonic metasurfaces fabricated out of giant magnetoresistance/spintronic materials in the 2–17 μm spectral range of the spectrum. The modulation of the slit plasmonic modes is due to the modification of the electrical resistivity (and, in turn, of the optical constants) induced by the application of an external magnetic field. This modulation is found to continuously increase both with the slit concentration and with the slit resonance wavelength, with a prospective further increase for wavelengths of up to 60–80 μm. The direct fabrication and implementation of the modulation setup opens a competitive route for the development of active plasmonic metasurfaces in a wide spectral range.