Plasmonic metamaterial for electromagnetically induced transparency analogue and ultra-high figure of merit sensor

Abstract

In this work, using finite-difference time-domain method, we propose and numerically demonstrate a novel way to achieve electromagnetically induced transparency (EIT) phenomenon in the reflection spectrum by stacking two different types of coupling effect among different elements of the designed metamaterial. Compared with the conventional EIT-like analogues coming from only one type of coupling effect between bright and dark meta-atoms on the same plane, to our knowledge the novel approach is the first to realize the optically active and precise control of the wavelength position of EIT-like phenomenon using optical metamaterials. An on-to-off dynamic control of the EIT-like phenomenon also can be achieved by changing the refractive index of the dielectric substrate via adjusting an optical pump pulse. Furthermore, in near infrared region, the metamaterial structure can be operated as an ultra-high resolution refractive index sensor with an ultra-high figure of merit (FOM) reaching 3200, which remarkably improve the FOM value of plasmonic refractive index sensors. The novel approach realizing EIT-like spectral shape with easy adjustment to the working wavelengths will open up new avenues for future research and practical application of active plasmonic switch, ultra-high resolution sensors and active slow-light devices.

A low-loss electromagnetically induced transparency (EIT) metamaterial based on coupling between electric and toroidal dipoles

“…To achieve EIT resonance, resonators with similar resonance frequencies and different Q factors are necessary. [12][13][14]28 In our conguration, by deliberately optimizing the parameters, the resonance responses of the SRRs and ICW resonators can satisfy the abovementioned conditions. As a consequence, SRRs with a high Q factor serve as the dark resonator, [4][5][6][7][12][13][14] whereas an ICW with a low Q factor acts as a bright resonator.…”

“…1(a), an EIT window appeared in the transmission spectra because of the destructive coupling of scattering elds between them, [4][5][6][7][12][13][14]17,25 as shown in Fig. 5(a).…”

“…[12][13][14] Generally, the electric dipole response serves as a bright resonance, and the magnetic dipole or quadrupole response serves as a dark resonance. However, the toroidal dipole as a third family multipole is usually ignored.…”

“…11 Dissipation loss can be minimized using a good conductor or dielectric material, whereas primary radiation loss can be reduced using destructive interference between bright and dark resonances, [12][13][14] known as Fano resonances or EIT effects. [12][13][14] Generally, the electric dipole response serves as a bright resonance, and the magnetic dipole or quadrupole response serves as a dark resonance.…”

Induced Transparency in Plasmon–Exciton Nanostructures for Sensing Applications

“…The interaction between light and matter, which results in induced optical transparency (IT), is of great interest for the development of various applications such as slow light systems, novel sensors, and low‐loss metamaterials . In atom optics, this effect can be observed in three‐level atoms interacting with two laser beams ( Figure a).…”