2016/04/30 by Adi Pick, Bo Zhen, Owen D. Miller +5 · 1 citation
Physics and Astronomy · #physics.optics
paper · pdf · doi:10.1364/oe.25.012325
published as Optics Express Vol. 25, Issue 11, pp. 12325-12348 (2017) · 15 pages, 7 figures
arxiv created 2017/05/18 · arxiv updated 2017/05/19
We present a general theory of spontaneous emission at exceptional points (EPs)---exotic degeneracies in non-Hermitian systems. Our theory extends beyond spontaneous emission to any light--matter interaction described by the local density of states (e.g., absorption, thermal emission, and nonlinear frequency conversion). Whereas traditional spontaneous-emission theories imply infinite enhancement factors at EPs, we derive finite bounds on the enhancement, proving maximum enhancement of 4 in passive systems with second-order EPs and significantly larger enhancements (exceeding 400×) in gain-aided and higher-order EP systems. In contrast to non-degenerate resonances, EPs are associated with non-Lorentzian emission curves, leading to enhancements that scale polynomially with the resonance quality factor.