3 Ways to View the Local Density of Optical States

The concept of the local density of optical states (widely referred to as "LDOS") is ubiquitous in nanophotonics as it serves to explain a wide range of electromagnetic phenomena, varying from antenna physics [1] , fluorescence [2] - [4] and emission control [5] , [6] , inter-molecular energy transfer [7] , [8] , and strong coupling [9] . Recently, we explored the fundamentals of this concept and its consequences in a broad didactic overview [10] . Here, we focus in greater detail on one of the wide-ranging implications from our study, namely our newly gained insights of how one can view the local density of states in several different ways. Each of these different approaches offers an alternative conceptual insight into the local density of optical states. Importantly, by making a detailed comparison between the different approaches we show the equivalence of rather different research fields, namely electrical engineering, quantum optics, and nanophotonics viewpoints.