Nonlinear THz‐Nano Metasurfaces

Abstract

Extreme terahertz (THz) science and technologies, the next disruptive frontier in nonlinear optics, provide multifaceted capabilities for exploring strong light‐matter interactions in a variety of physical systems. However, current techniques involve the need for an extremely high‐field free space THz source that is difficult to generate and has limited investigations to a rather weak and linear regime of light‐matter interactions. Therefore, new approaches are being sought for the tight confinement of THz waves that can induce nonlinear effects. Here, a nonlinear “tera‐nano” metasurface is demonstrated exhibiting extremely large THz nonlinearity and sensitive self‐modulation of resonances at moderate incident THz field strengths. A record deep‐subwavelength (≈λ/33 000) confinement of strongly enhanced (≈3200) THz field in a nano‐gap (15 nm) exhibits remarkable THz field‐tailored nonlinearity. Further, ultrafast injection of photocarriers reveals a competition between nonlinear THz field‐induced intervalley scattering and optically driven interband excitations. The results on “tera‐nano” metasurfaces enable a novel platform to realize enhanced nonlinear nano/micro composites for field‐sensitive extreme THz nonlinear applications without the need for intense THz light sources.

Reconfigurable terahertz metamaterials: From fundamental principles to advanced 6G applications

“…In conclusion, with the rapid development of critical science and technology in recent years, metamaterial-based THz photonics have been developed toward a standard and robust platform to achieve basic tunability for more functional applications. On the one hand, higher tunability, faster response rate, and lower power consumption are the challenges that remain for more commercial applications ( Li et al., 2020a ) ( Manjappa and Singh, 2020 ; Agarwal et al., 2021 ; Dong et al., 2021 ; Pitchappa et al., 2021b ). On the other hand, systematical work that required high integration and feasible software platform is also current blocks to be overcome ( Wu et al., 2019 ; Wan et al., 2021 ).…”

Spintronic terahertz emission with manipulated polarization (STEMP)

“…1c), and particle acceleration . Hindering the reproduction of THz techniques lies in the shortage of highly efficient THz sources [2], sensitive THz detectors [3], and various functional devices [32][33][34][35], as well as cost-effective integrated THz systems [1, 5-7, 27, 29].…”

Enhanced Terahertz Transmission in Molybdenum Disulfide/Silicon Heterojunction

“…[17,18] Conventional THz modulation materials concentrate on semiconductors, metamaterials, phase transition materials, magnetic materials, strain materials, and their compounds. [19][20][21][22][23] In parallel to these recent advances at the intersection of THz and material sciences, there have been major progress in 2D materials. [24] For instance, tunable perfect THz absorbers were demonstrated with near-zero reflection using integrated metallic gratings into the classical Salisbury screen structure based on graphene.…”