Manipulating the plasmon-induced transparency in terahertz metamaterials

Abstract

Coupling between superradiant and subradiant mode resonators in a metamaterial unit cell plays an important role in observing the sharp transparency peak due to destructive interference between the resonators. This effect is enhanced as the resonators are brought closer to each other in a conventional planar arrangement. We present a novel coupling scheme of planar terahertz metamaterial to tune the plasmon-induced transparency peak by physically varying the distance between the superradiant and the subradiant resonators in such a way that the transparency peak begins to disappear as the coupled resonators are brought closer than a critical separation distance. The effect is attributed to the disappearance of the resonant behavior of the subradiant resonator in a closely coupled regime. The simple planar design presented here demonstrates a scheme to manipulate the electromagnetically induced transparency-like behavior in terahertz metamaterials and this could lead to the development of unique slow light devices for terahertz applications.

Electromagnetically Induced Absorption in Metamaterials in the Infrared Frequency

“…DISCUSSION Figure 7 shows the transmission spectra of the EIT and EIA structures as a function of the symmetry parameter s, we see that the narrow transmission/absorption window becomes more pronounced and shifted to lower frequencies for the EIA structure as the s parameter increases. For s = 0 the EIT and EIA disappear as breaking symmetry is a requirement for both the EIT and EIA effect [8][9][10][11][12][13][14].…”

“…A bright mode element couples strongly with the incident excitation field while the dark element does not couple with the incident field but couples with the magnetic field induced by the bright element. Several EIT metamaterial structures have been employed and reported in the microwave, terahertz and optical frequency regions [8][9][10][11][12][13][14].…”

Polarization-independent and angle-insensitive electromagnetically induced transparent (EIT) metamaterial based on bi-air-hole dielectric resonators

“…1,4,5 This phenomenon can be explained by quantum interference between the pump and probe beams tuned at different transitions. [6][7][8] This EIT effect is usually accompanied with strong dispersion, leading to a large value of the effective group index, which is important for slow light control. 2,8,9 Besides, nonlinear optics, ultrafast switching, optical data storage, signal processing, optical delay lines and many other intriguing applications have been further developed based on the EIT effect.…”

“…2,8,9 Besides, nonlinear optics, ultrafast switching, optical data storage, signal processing, optical delay lines and many other intriguing applications have been further developed based on the EIT effect. 7,9,10 Recently, with the rapid development of metamaterials, the analog of EIT effect in metamaterials has captured signicant attention of researchers. This is because the EIT effect can be easily realized in microwave, terahertz, and optical ranges.…”

“…This is because the EIT effect can be easily realized in microwave, terahertz, and optical ranges. 7,11,12 Moreover, compared with the EIT property in atomic systems, the EIT effect in metamaterials has the advantages of bandwidth broadening, room temperature operation, nanoscale planar devices, and the ability to integrate with nanoplasmonic circuits, which allow the use of the EIT effect in practical applications. [13][14][15] Generally, the EIT effect in metamaterials is realized based on two methods: one is the bright-dark model, and the other is the superradiant-subradiant model.…”