Document Type
Article
Publication Date
10-30-2017
Abstract
We introduce a non-parity-time-symmetric three-layer structure, consisting of a gain medium layer sandwiched between two phase-change medium layers for switching of the direction of reflectionless light propagation. We show that for this structure unidirectional reflectionlessness in the forward direction can be switched to unidirectional reflectionlessness in the backward direction at the optical communication wavelength by switching the phase-change material Ge2Sb2Te5 (GST) from its amorphous to its crystalline phase. We also show that it is the existence of exceptional points for this structure with GST in both its amorphous and crystalline phases which leads to unidirectional reflectionless propagation in the forward direction for GST in its amorphous phase, and in the backward direction for GST in its crystalline phase. Our results could be potentially important for developing a new generation of compact active free-space optical devices.
Publication Source (Journal or Book title)
Optics Express
First Page
27283
Last Page
27297
Recommended Citation
Huang, Y., Shen, Y., Changjun, M., & Veronis, G. (2017). Switching of the direction of reflectionless light propagation at exceptional points in non-PT-symmetric structures using phase-change materials. Optics Express, 25 (22), 27283-27297. https://doi.org/10.1364/OE.25.027283