Slow Light Propagation and Disorder-Induced Localization in Photonic Crystal Waveguides

Abstract

We investigate the phenomenon of slow-light propagation in planar photonic crystal waveguides and present a theoretical formalism and matching experiments to describe disorder-induced coherent scattering. The theory uses a coupled-mode approach to track multiple forward and backward reflections and a rigorous Green function technique to introduce the effect of disorder. Simulaphotonic crystal membranes are compared through transmission measurements and frequency-delay reflectometry. The excellent qualitative agreement between theory and experiment provides clear physical insight into naturally occurring light localization and multiple coherent-scattering phenomena in slow-light waveguides. Further, we briefly connect with related phenomena of absorption-induced losses in slow-light metamaterial waveguides.

Strongly coupled slow-light polaritons in one-dimensional disordered localized states

“…Alternatively, one-dimensional photonic crystal waveguides enable an increased local density of states at the slow-light band edge for enhanced light-matter interactions while affording ease of photon extraction, with recent Purcellenhanced spontaneous emission demonstrations [21][22][23][24] and photon transport dynamics predictions [25]. With coherent interference and scattering at the slow-light band edge through inherent nanometer-scale fabrication fluctuations, high-Q localized modes near the band edge were recently examined [26][27][28][29][30]. This enabled the remarkable observations of controlled spontaneous emission in single quantum dots through engineered disordered localized waveguide modes [21], though only in the weak coupling regime.…”