Passive Transmission Symmetry Breaking Without Non-Reciprocity in All-Dielectric Metagratings

While reflection symmetry can be routinely broken in a passive system by introducing loss the same is not true for transmission symmetry. Passive and linear systems exhibit transmission symmetry because of the reciprocity principle. In other words, it would appear that breaking transmission symmetry in a linear passive system would be synonymous to breaking reciprocity.<br/><br/>In this talk, we will present a specially designed metagrating that possesses several output channels, as a result of higher-order Bragg beams being triggered. We will discuss the transmission response of this system, exhibiting a strong asymmetry, with contrast as high as ~75% [1]. We analyze the underpinning mechanism and explain how a transmission asymmetry in this type of system remains consistent with the reciprocity principle. We further verify such transmission asymmetric behavior with an FDTD numerical experiment.<br/><br/>We believe this transmission asymmetry capability in these simple systems without requiring non-reciprocity can open-up new avenues for photonic components design across the EM spectrum.<br/><br/>[1] S. Foteinopoulou, Breaking Transmission Symmetry Without Breaking Reciprocity in Linear All-Dielectric Polarization-Preserving Metagratings, Phys. Rev. Applied 17, 024064 (2022); https://doi.org/10.1103/PhysRevApplied.17.024064