Tunable spatial Goos-Hänchen shift in periodic PT-symmetric photonic crystals with a central defect

Abstract

The Goos-Hänchen (GH) effects are investigated for a transverse magnetic beam totally reflected by periodic PT-symmetric photonic crystals. A dielectric layer with a real refractive index situates as a defect in the center. Both positive and negative spatial GH shifts are induced around the defect mode. The GH shifts sensitively change with the refractive index of the defect layer. More importantly, giant negative GH shift effect with big reflectance could be found and modulated by increasing the gain-loss factor in PT-symmetric systems, which could improve the detecting sensitivity of the defect. Our study may be valuable in potential applications for highly sensitive sensors.