Nature of the enhanced resonant modes in one-dimensional photonic random dimer systems

The propagation of light in a one-dimensional multilayer stack is examined for a disordered system with short range correlation. As known in the random dimer model, pairing the defect elements at random breaks down the Anderson localization and opens a frequency window of extended propagating modes around the predicted conventional dimer resonance. By dealing with host and defect layers with identical phase thicknesses at both host and defect principal standing resonances, we demonstrate the existence of a new ballistic-like regime at an additional standing commuting resonance. Moreover, by suitably tuning the host standing and conventional defect dimer resonances relative to each other, the transmission responses are both turned into a ballistic transmission regime. By scaling the transmission coefficient over the system length within the resonance window, we analyse the nature of the propagating modes, i.e.ballistic or diffusive. Beyond the resonance, quantitative views on the different transmission regimes and their related phase transitions are examined, pointing out the possibility of designing attractive ballistic resonant optical devices with adjustable transmission responses.