Highly flexible broadband terahertz metamaterial quarter‐wave plate

Abstract

Metamaterials offer exciting opportunities that enable precise control of light propagation, its intensity and phase by designing an artificial medium of choice. Inducing birefringence via engineered metamolecules presents a fascinating mechanism to manipulate the phase of electromagnetic waves and facilitates the design of polarimetric devices. In this paper, a high‐efficiency, broadband, tunable and flexible quarter‐wave plate based on a multilayer metamaterial is presented. Excellent achromatic π/2 phase retardance with high transmission is observed upon terahertz propagation through the quarter‐wave plate. The calculated Stokes parameter represents the output polarization state numerically, indicating an excellent broadband conversion of linearly polarized light into circularly polarized light. The metamaterial‐based quarter‐wave plate demonstrated in this work could be an important step forward in the development of functional terahertz polarization conversion devices for practical applications.

Broadband tunable liquid crystal terahertz waveplates driven with porous graphene electrodes

“…In fact, graphene films, including porous ones, could replace the metal wire grid electrode both here and in other devices. 31,32 The effective LC thickness was nearly doubled, thereby allowing the device to function as a quarterwave plate over the entire testing range (0.5-2.5 THz). A DQ tuning of 0-p for frequencies above 0.9 THz (red and yellow regions in Figure 5b) and even a tuning of over 2p for frequencies above 1.8 THz (yellow regions in Figure 5b) were achieved.…”

Broadband High-Efficiency Half-Wave Plate: A Supercell-Based Plasmonic Metasurface Approach

“…[17][18][19] Detuning the plasmonic resonator away from their resonant wavelengths is a good 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 4 approach to realize broadband polarization conversion. [20][21][22][23][24] Additionally, dispersion-free meta-structures are used to broaden the operational bandwidth. 25,26 Another issue that matters is the extremely low polarization conversion efficiency of plasmonic metasurfaces, coming from the weak coupling between the incident and cross-polarized fields.…”

Achromatic polarization manipulation by dispersion management of anisotropic meta-mirror with dual-metasurface

“…Nevertheless, conventional polarization devices are cumbersome, which do not lend themselves to photonic system integration. As compelling candidates, metamaterials have been widely employed to realize polarization control in microwave [2][3][4][5][6][7][8][9], terahertz [10,11], infrared [12], and visible band [13,14] during the past decade. Especially, two-dimensional metamaterials (i.e., metasurfaces) will ease the fabrication requirements and provide additional freedom in wavefront manipulation due to the phase abruption along a thin interface [15][16][17][18].…”