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Results for “terahertz metamaterials”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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21 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Lightwave-driven electron emission for polarity-sensitive terahertz beam profiling

The full exploitation of advanced light sources in the terahertz (THz) frequency range requires versatile experimental tools to fully characterize the spatial, temporal, and spectral shapes of the THz electric field. Several techniques for passive THz beam profiling exist that offer information about the temporally integrated intensity. Thus, any information about the electric field itself is lost. Here, we show that a UV–visible light emission produced via a lightwave-driven field emission from single-layer metasurfaces can be used to visualize the peak electric field distribution of THz beams in real time. Our technique is scalable up to frequencies approaching the plasma frequency of the metal used for the metasurface. Uniquely, our device is sensitive to the absolute polarity of the THz lightwave. These findings demonstrate a general pathway to designing metamaterial-based field-sensitive optical detectors suitable for the entire THz and IR spectral region.

42 ENGINEERING↗
DOE OSTI2022

Realizing symmetry-guaranteed pairs of bound states in the continuum in metasurfaces

Abstract Bound states in the continuum (BICs) have received significant attention for their ability to enhance light-matter interactions across a wide range of systems, including lasers, sensors, and frequency mixers. However, many applications require degenerate or nearly degenerate high-quality factor ( Q ) modes, such as spontaneous parametric down conversion, non-linear four-wave mixing, and intra-cavity difference frequency mixing for terahertz generation. Previously, degenerate pairs of bound states in the continuum (BICs) have been created by fine-tuning the structure to engineer the degeneracy, yielding BICs that respond unpredictably to structure imperfections and material variations. Instead, using a group theoretic approach, we present a design paradigm based on six-fold rotational symmetry ( C 6 ) for creating degenerate pairs of symmetry-protected BICs, whose frequency splitting and Q -factors can be independently and predictably controlled, yielding a complete design phase space. Using a combination of resonator and lattice deformations in silicon metasurfaces, we experimentally demonstrate the ability to tune mode spacing from 2 nm to 110 nm while simultaneously controlling Q -factor.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2024

Combinatorial split-ring and spiral metaresonator for efficient magnon-photon coupling

Developing hybrid materials and structures for electromagnetic wave engineering has been a promising route towards novel functionalities and tunabilities in many modern applications. Despite its established success in engineering optical light and terahertz waves, the implementation of metaresonators operating in the microwave band is still emerging, especially the implementation of metaresonators that allow on-chip integration and size miniaturization, which is crucial for developing hybrid quantum systems in the microwave band. In this work, we present a microwave metaresonator consisting of split-ring and spiral resonators, and implement it for the investigation of photon-magnon coupling for hybrid magnonic applications. We observe broadened bandwidth of the split-ring modes augmented by the additional spiral resonator, and, by coupling the modes to a magnetic sample, the resultant photon-magnon coupling can be significantly enhanced by more than tenfold. Furthermore, our work suggests that combinatorial, hybrid microwave resonators may be a promising approach towards future development and implementation of photon-magnon coupling in hybrid magnonic systems.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗