Angular-Dependent THz Modulator with Hybrid Metal-Graphene Metastructures

Abstract

The coupling effects of surface plasmon resonance (SPR) from metamaterials induce variation in both the frequency and intensity of plasmonic modes. Here, we report an angular-dependent THz modulator with hybrid metal–graphene metastructures. The metastructures composed of the period gold split-rod arrays on top of a monolayer graphene, which show redshift modulation in the THz region with an increasing incident angle due to the strong out-of-plane magnetic flux introduced by the clockwise circular current at the oblique incidence. By utilizing graphene-based actively tunable conductor with ion-gel electrical gating, the THz transmission can be significantly modified. The modulation depth of the hybrid metal–graphene metastructure modulator can reach ~37.6% at 0.62 THz with a gate voltage of −3 V. The theoretical modeling of transmitted dependency on frequency and incident angle is demonstrated at different Fermi energies, which fits well with the experimental results. This hybrid device can offer a useful method for THz applications (such as angle sensors or angular-resolved spectroscopy), where angle-dependent modulation is needed.

Editorial of the Special Issue ‘Nano-Optics and Nano-Optoelectronics: Challenges and Future Trends’

“…To explore the latest developments and challenges and the future trends in nano-optics and nano-optoelectronics, this Special Issue compiles sixteen papers dedicated to very recent advances in nanostructures and nanomaterials. In these papers, novel nanostructures and nanomaterials, such as metastructures [ 1 , 2 , 3 ], metalenses [ 4 , 5 ], nanoparticles [ 6 , 7 ], layered 2D materials [ 8 , 9 ], and nano-semiconductors [ 10 , 11 ], are presented in detail. Due to their exceptional properties, these nanostructures/nanomaterials offer a diverse range of novel applications in photodetectors [ 1 , 9 , 11 ], solar cells [ 2 , 9 , 10 ], modulators [ 1 , 3 , 8 ], light emitters [ 1 , 7 ], optoelectronic integration [ 5 , 6 ], super-resolved imaging [ 4 , 5 ], nanofabrication [ 4 ], etc.…”

“…In these papers, novel nanostructures and nanomaterials, such as metastructures [ 1 , 2 , 3 ], metalenses [ 4 , 5 ], nanoparticles [ 6 , 7 ], layered 2D materials [ 8 , 9 ], and nano-semiconductors [ 10 , 11 ], are presented in detail. Due to their exceptional properties, these nanostructures/nanomaterials offer a diverse range of novel applications in photodetectors [ 1 , 9 , 11 ], solar cells [ 2 , 9 , 10 ], modulators [ 1 , 3 , 8 ], light emitters [ 1 , 7 ], optoelectronic integration [ 5 , 6 ], super-resolved imaging [ 4 , 5 ], nanofabrication [ 4 ], etc. This Special Issue also encompasses the latest advancements in practical nano-optical and nano-optoelectronic technologies, such as femtosecond laser nano-processing [ 12 ], atomic layer coating [ 13 ], and new designs for photonic integration engineering [ 14 ].…”

“…The proposed PMA exhibits remarkable absorption in both TE and TM modes and insensitivity to polarization and incident angles. Wang et al [ 3 ] present a novel angular-dependent THz modulator that utilizes hybrid metal–graphene metastructures. Theoretical and experimental analyses show that the hybrid device offers a promising approach to applications in the field of THz technology.…”