Nonpolarizing narrow band metamaterial transmission filter based on electromagnetically induced transparency at visible wavelengths

A nonpolarizing narrow band metamaterial transmission filter based on EIT operating at visible wavelengths is demonstrated theoretically and experimentally. The two separated resonance components that are able to generate EIT effect are connected using a SiO₂ film layer and the hardness of the metamaterial filter is further improved by adding a glass substrate. The theoretical results are calculated by using the finite-difference time-domain simulation method and a metamaterial filter sample is fabricated and measured to verify the simulation spectrum. The full width at half-maximums of simulation and measured spectra are 0.74 nm and 1.61 nm respectively. Electric field distributions are also calculated to illustrate the physical mechanism. The novel method might be helpful to improve the processability of the narrow band metamaterial transmission filter, and also to further promote the applications of this kind of metamaterial filter.