Fan, ShanhuiShanhuiFanBaets, RoelRoelBaetsPetrov, AlexanderAlexanderPetrovYu, ZongfuZongfuYuJoannopoulos, John D.John D.JoannopoulosFreude, WolfgangWolfgangFreudeMelloni, AndreaAndreaMelloniPopović, MilošMilošPopovićVanwolleghem, MathiasMathiasVanwolleghemJalas, DirkDirkJalasEich, ManfredManfredEichKrause, MichaelMichaelKrauseRenner, HagenHagenRennerBrinkmeyer, ErnstErnstBrinkmeyerDoerr, ChristopherChristopherDoerr2019-09-202019-09-202012-01-06Science 6064 (335): 38 (2012)http://hdl.handle.net/11420/3387We show that the structure demonstrated by Feng et al. (Reports, 5 August 2011, p. 729) cannot enable optical isolation because it possesses a symmetric scattering matrix. Moreover, one cannot construct an optical isolator by incorporating this structure into any system as long as the system is linear and time-independent and is described by materials with a scalar dielectric function.en1095-92032012606438American Association for the Advancement of SciencePhysikJournal Article10.1126/science.1216682Other