Improved photon-pair generation from transition-metal dichalcogenide monolayers embedded in one-dimensional photonic crystals

摘要

We have theoretically investigated photon-pair generation from transition-metal dichalcogenide (TMDC) monolayers embedded in photonic crystals (PCs) by a rigorous quantum model of spontaneous parametric downconversion. The mean number of output photon pairs and the signal-field energy spectrum have been elaborated. Two different structures are studied: one is a monolayer WS2 embedded in the defective PC, and the other is a stack of WS2 layers in the dielectric multilayer structure. It is clearly shown that an obvious improvement of the generation rate of the correlated photon pairs from the monolayer WS2 can be realized in these two structures, and the enhancement can reach as much as 14 orders of magnitude. Such an effective improvement utilizes the improved field localization at the defect state or the band-edge state, the propagation of photons in the PCs, and coherent superposition; similar phenomena can occur for other TMDC monolayers. These phenomena are very beneficial for the design of optical devices. (c) 2018 Optical Society of America