2018/10/31 by Hanwen Zhang, Chia Wei Hsu, Owen D. Miller · 31 citations
Engineering · Materials Science · Physics and Astronomy · #Acoustic Wave Phenomena Research #Brightness #Computation #Field (mathematics) #Inverse #Inverse scattering problem #Measure (data warehouse) #Metamaterials and Metasurfaces Applications #Plasmonic and Surface Plasmon Research #Power (physics) #Scattering #physics.optics
paper · pdf · open access · doi:10.1364/optica.6.001321
published in Optica 6(10), 1321 (Optica Publishing Group)
openalex created_date 2019/03/02 · arxiv created 2019/09/02 · openalex publication_date 2019/10/01 · arxiv updated 2019/10/24 · openalex updated_date 2026/08/05
The brightness theorem---brightness is nonincreasing in passive systems---is a foundational conservation law, with applications ranging from photovoltaics to displays, yet it is restricted to the field of ray optics. For general linear wave scattering, we show that power per scattering channel generalizes brightness, and we derive power-concentration bounds for systems of arbitrary coherence. The bounds motivate a concept of "wave 'etendue" as a measure of incoherence among the scattering-channel amplitudes, and which is given by the rank of an appropriate density matrix. The bounds apply to nonreciprocal systems that are of increasing interest, and we demonstrate their applicability to maximal control in nanophotonics, for metasurfaces and waveguide junctions. Through inverse design, we discover metasurface elements operating near the theoretical limits.