Liquid Crystal Switchable Surface Lattice Resonances in Plasmonic Metasurfaces

Surface lattice resonances (SLRs) on metasurfaces strongly enhance the interaction of light with the metasurface and can be used for obtaining very high-Q response, high spectral sensitivity, and strong optical nonlinearities. Here, we study experimentally and numerically the dynamic switching of SLRs in gold nanoantenna metasurfaces fabricated on top of indium tin oxide by use of electrically controlled liquid crystals. Experimental results show that the cumulative effects of the anisotropic optical response with an applied electric field and the alignment conditions of liquid crystal molecules significantly affect the formation as well as the strength of SLR modes. We achieve an electrical modulation of >50% in the SLR dips by applying 2 V on the device. The strength of the modulation can be further optimized by modifying the angle of incidence and the polarization of light. These findings demonstrate that plasmonic metasurfaces activated by liquid crystals enable a versatile platform to obtain electro-optical control over SLRs and open the door to various new applications of dynamic reconfigurable metasurfaces.