Optical Chiral Response of MXene Nanoantenna Lattice

The chiral response from nanoantennas is useful for enabling advanced applications in areas such as optical communication, sensing, and imaging, due to its ability to selectively interact with circularly polarized light. Lattice resonances in periodic nanoantenna arrays can enhance the optical response of the nanostructure and facilitate stronger light-matter interaction. We design a nanoantenna array made of highly conductive layered MXene material, capitalizing on the lattice's unique properties to control the optical response. We demonstrate the chiral properties of this periodic array of MXene nanoantennas, and these properties are defined by the lattice periodicity. Despite being a lossy optical material in the near-infrared range, the lattice arrangement of MXene facilitates the excitation of stronger resonances, thereby enhancing its overall response. Utilizing chiral periodic lattices presents a promising avenue to significantly enhance the chiral response in lossy materials, including but not limited to MXene, transition metal dichalcogenides, and lossy metals

Bismuth ferrite as low-loss switchable material for plasmonic waveguide modulator

We propose new designs of plasmonic modulators, which can be utilized for dynamic signal switching in photonic integrated circuits. We study performance of plasmonic waveguide modulator with bismuth ferrite as an active material. The bismuth ferrite core is sandwiched between metal plates (metal-insulator-metal configuration), which also serve as electrodes so that the core changes its refractive index under applied voltage by means of partial in-plane to out-of-plane reorientation of ferroelectric domains in bismuth ferrite. This domain switch results in changing of propagation constant and absorption coefficient, and thus either phase or amplitude control can be implemented. Efficient modulation performance is achieved because of high field confinement between the metal layers, as well as the existence of mode cut-offs for particular values of the core thickness, making it possible to control the signal with superior modulation depth. For the phase control scheme, {\pi} phase shift is provided by 0.8-{\mu}m length device having propagation losses 0.29 dB/{\mu}m. For the amplitude control, we predict up to 38 dB/{\mu}m extinction ratio with 1.2 dB/{\mu}m propagation loss. In contrast to previously proposed active materials, bismuth ferrite has nearly zero material losses, so bismuth ferrite based modulators do not bring about additional decay of the propagating signal