title: Thermodynamic upper bound on broadband light coupling with photonic structures.
abstract: The coupling between free space radiation and optical media critically influences the performance of optical devices. We show that, for any given photonic structure, the sum of the external coupling rates for all its optical modes are subject to an upper bound dictated by the second law of thermodynamics. Such bound limits how efficient light can be coupled to any photonic structure. As one example of application, we use this upper bound to derive the limit of light absorption in broadband solar absorbers.
authors.affiliation: Ginzton Laboratory, Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Zongfu
authors.initials: Z
authors.lastname: Yu
authors.forename: Aaswath
authors.initials: A
authors.lastname: Raman
authors.forename: Shanhui
authors.initials: S
authors.lastname: Fan