Chiral and bianisotropic materials
15:00 : Optical diode with topological insulators and chiral media
Filipa Prudencio (1),Mario Silveirinha (2)
(1)Instituto Superior Tecnico-Instituto de Telecomunicaoes (Portugal) , (2)Universidade de Coimbra-Instituto de Telecomunicaoes (Portugal) An asymmetric light flow requires a broken time-reversal symmetry , and is traditionally achieved with the help of either an external magnetic field or with nonlinear elements. Here, we explore the opportunities offered by materials with a spontaneous nonreciprocal response in the one-way propagation of light. We theoretically demonstrate a new paradigm for optical isolation using antiferromagnet topological insulators, combined with chiral media.
15:15 : Reducing the complexity: Strong single-handed chiral near-fields in diagonal slits
Martin Schaferling (1),Nader Engheta (2),Thomas Weiss (1),Harald Giessen (1)
(1)University of Stuttgart (Germany) , (2)University of Pennsylvania (USA) We demonstrate a novel plasmonic design to generate near-fields with strong optical chirality for enantiomer sensing applications. Our design, which consists of diagonal slits on top of a mirror, features homogeneous chiral near-fields of one handedness that are easy to access. The diagonal-slit structure is simple to fabricate and allows for straightforward tuning of the operating wavelength. We demonstrate its properties and present optimization strategies using numerical simulations. Additionally, we discuss potential applications as a sensor for enantiomer discrimination.
15:30 : Cramer-Rao Bounds for Anisotropic and Bianisotropic Metasurfaces Susceptibilities
Thomas Lepetit, Boubacar Kante
University of California San Diego (USA) Accurate and robust characterization of metasurfaces in terms of effective parameters is critical to the design of metadevices. We compute the Cramer-Rao lower bounds on the variance of any estimator for the electric, magnetic, and magneto-electric surface susceptibilities. We show that retrieval of such effective properties is inherently difficult around resonances, most notably for low-loss metasurfaces. The present work is relevant to the development of loss-compensated metasurfaces for which noise has to be closely considered for device characterization.