Ultra-narrow electromagnetically induced transparency in the visible and near-infrared regions

摘要

The electromagnetically induced transparency (EIT) phenomenon is of great importance for plenty of applications, such as slow light, nonlinear effect, nanosensing, and metamaterials. The linewidth is a key factor to evaluate the characteristic of EIT, because the drastic change in dispersion in the narrow spectra can make good control of light. However, only a few reports are related to the ultranarrow EIT. In this paper, we propose a nanosystem based on a gold grating and a multilayer structure. An ultranarrow spectral EIT peak with a linewidth range of 0.75-1.5nm is observed in such a nanosystem in the visible and near-infrared regions. The physical mechanism leading to the phenomenon is different from those in previous works. In the proposed nanosystem, the ultranarrow EIT peak is formed by the destructive interference of the Fabry-Perot resonance and waveguide modes. Analytic results calculated from the model equations are also found to be consistent with numerical simulations for both normal and oblique incidences. Our work provides another efficient way to realize an ultranarrow EIT.