Nonvolatile Reconfigurable Electromagnetically Induced Transparency with Terahertz Chalcogenide Metasurfaces

Abstract

Metasurface analog of electromagnetically induced transparency (EIT) provides a compact platform for generating a narrow-band transmission window with very sharp spectral features. They hold promise for many appealing applications including ultrasensitive detectors, slow-light devices, nonlinear optical devices etc. In particular, reconfigurable EIT metasurfaces are crucial for expanding the capability of light field control, which are promising for terahertz (THz) communications and optical networks. Yet, the investigation on reconfigurable EIT metasurfaces with nonvolatile operation remains scarce. Here, reversible switching of the metasurface-induced transparency in the THz spectrum is experimentally realized. The reconfigurable response (reversible spectral shift) is obtained by integrating a nonvolatile chalcogenide phase change material, Ge 2 Sb 2 Te 5 (GST225) into the meta-atoms. A giant reversible switching of EIT takes place under an excitation of nanosecond laser pulses, showing a reconfigurable group delay of the THz waves. The proposed reconfigurable THz metadevices may provide a new route for the ultrafast laser induced switching and reconfigurable slow-light devices.

Nonvolatile Switchable Broadband Polarization Conversion with Wearable Terahertz Chalcogenide Metamaterials

“…The slight discrepancy between the experiment and simulation was possibly caused by the presence of a rough surface and imperfect fabrication. [ 29 ] For the amorphous state (Figure 3c), it was revealed that such wideband and high‐efficiency performance was sustained over a broad θ i range from 0° to 75° with a step of 2°. The broadband operation stemmed from multiple peak polarization conversion superposition around 0.68, 1, and 1.48 THz.…”

“…[26] Chalcogenide alloy (i.e., Ge-Sb-Te, GST) is a typical phase change material (PCM) possessing significantly different optical characteristics at the different crystallographic phases of amorphous and crystalline, [27] showing a talented candidate for obtaining the tunable metamaterials. [28,29] Nucleation dynamics drove the phase change of GST. [30] By continuously modulating the crystallization portion of GST, one can achieve the analog response instead of binary transition phases.…”

Transmissive angle-multiplexed meta-polarizer based on a multilayer metasurface

“…Recently, metasurfaces, two-dimensional metamaterials constructed by planar meta-atoms with designable EM responses arranged in some specific global orders, have shown great capabilities to manipulate EM waves with many fascinating effects discovered [1][2][3] , including anomalous reflection/refraction [4][5][6] , meta-lensing [7][8][9] , polarization conversion [10][11][12][13] , meta-hologram [14][15][16][17] , surface-wave manipulations [18][19][20][21] , electromagnetically induced transparency [22] , and many others [23][24][25][26][27][28][29] . Since the metasurface is flat and ultra-thin, it forms an ideal platform to realize multifunctional EM devices.…”

Dual-band electromagnetically induced transparency terahertz metamaterial based on U-like resonator and metallic cut wire for sensing application

“…Since there are few natural materials with specific electromagnetic responses in the THz band, metamaterials (MMs) composed of artificially designed subwavelength resonators offer great application prospects in the manipulation of electromagnetic waves [8][9][10]. The electromagnetic properties of MMs are determined not by their constitutive materials but by their periodic unit structures.…”