Bidirectional Electromagnetically Induced Transparency Based on Coupling of Magnetic Dipole Modes in Amorphous Silicon Metasurface

Abstract

A bidirectional electromagnetically induced transparency (EIT) arising from coupling of magnetic dipole modes is demonstrated numerically and experimentally based on nanoscale a-Si cuboid-bar metasurface. Analyzed by the finite-difference time-domain (FDTD) Solutions, both the bright and dark magnetic dipole mode is excited in the cuboid, while only the dark magnetic dipole mode is excited in the bar. By breaking the symmetry of the cuboid-bar structure, the destructive interference between bright and dark magnetic dipole modes is induced, resulting in the bidirectional EIT phenomenon. The position and amplitude of simulated EIT peak is adjusted by the vertical spacing and horizontal spacing. The EIT metasurface was fabricated by Electron-Beam Lithography and deep silicon etching technique on the a-Si film deposited by Plasma-Enhanced Chemical Vapor Deposition. Measured by a convergent spectrometer, the fabricated sample achieved a bidirectional EIT peak with transmission up to 65% and 63% under forward and backward incidence, respectively. Due to the enhanced magnetic field induced by the magnetic dipole resonance, the fabricated bidirectional EIT metasurface provides a potential way for magnetic sensing and magnetic nonlinearity.

High-Performance Asymmetric Optical Transmission Based on a Dielectric–Metal Metasurface

“…Fortunately, the emergence of metamaterial provides an appealing alternative to control electromagnetic wave manipulations properties [12][13][14][15][16][17], and the discovery of the AT phenomenon based on metamaterial was first experimentally demonstrated in the microwave region by Fedotov et al in 2006 [18]. Since then, various AT devices based on artificial structures have been proposed which use photonic crystals [19,20], subwavelength asymmetric gratings [21][22][23][24], chiral metamaterials [25][26][27] and metasurfaces [28][29][30], and the operation wavelengths have been covered from microwave to visible light [31][32][33].…”

Thermally controlled electromagnetically induced transparency metamaterial through the near-field coupling of electric and toroidal resonances

“…Metamaterials are artificial sub-wavelength structures capable of producing diverse electromagnetic responses that are unattainable in natural materials [5][6][7][8][9][10][11]. Currently, a multitude of EIT metamaterials are being proposed and rigorously investigated for diverse materials [12][13][14][15][16], structures [17][18][19], tunable properties [20][21][22][23][24][25][26], and more. Within these EIT metamaterials, the coupling of bright and dark modes resonators emerges as an effective approach.…”

“…Liu et al conducted numerical and experimental investigations of an EIT metamaterial resulting from the coupling of magnetic dipole modes. Here, a bidirectional EIT phenomenon was induced by the structural symmetry breaking [20]. Nonetheless, these EIT metamaterials predominantly focus on electric or magnetic coupling modes, and the utilization of toroidal resonance, a third resonance mode in addition to electric and magnetic resonances, is infrequently incorporated within EIT schemes.…”

Active dual-control electromagnetically induced transparency analog in metal- vanadium dioxide-photosensitive silicon hybrid metamaterial

“…Metamaterials, artificial structures with subwavelength features, encompass a class of materials capable of generating phenomena often inaccessible or difficult to achieve in nature [5][6][7][8][9][10][11]. Consequently, numerous proposals for EIT metamaterials are emerging, expanding its practical utilization [12][13][14][15][16][17][18][19].…”