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Terahertz radiation

About: Terahertz radiation is a research topic. Over the lifetime, 40680 publications have been published within this topic receiving 611883 citations. The topic is also known as: THF & tremendously high frequency.


Papers
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Journal ArticleDOI
TL;DR: Terahertz irradiation and sensing is being applied for the first time to a wide range of fields outside the traditional niches of space science, molecular line spectroscopy, and plasma diagnostics as discussed by the authors.
Abstract: Terahertz irradiation and sensing is being applied for the first time to a wide range of fields outside the traditional niches of space science, molecular line spectroscopy, and plasma diagnostics. This paper surveys some of the terahertz measurements and applications of interest in the biological and medical sciences.

1,090 citations

Journal ArticleDOI
Tony Low1, Phaedon Avouris1
TL;DR: The basic properties of graphene plasmons are reviewed: their energy dispersion, localization and propagation, plasmon-phonon hybridization, lifetimes and damping pathways, and emerging and potential applications.
Abstract: In recent years, we have seen a rapid progress in the field of graphene plasmonics, motivated by graphene's unique electrical and optical properties, tunabilty, long-lived collective excitation and their extreme light confinement. Here, we review the basic properties of graphene plasmons; their energy dispersion, localization and propagation, plasmon-phonon hybridization, lifetimes and damping pathways. The application space of graphene plasmonics lies in the technologically significant, but relatively unexploited terahertz to mid-infrared regime. We discuss emerging and potential applications, such as modulators, notch filters, polarizers, mid-infrared photodetectors, mid-infrared vibrational spectroscopy, among many others.

1,056 citations

Journal ArticleDOI
18 Nov 2004-Nature
TL;DR: It is shown how a simple waveguide, namely a bare metal wire, can be used to transport terahertz pulses with virtually no dispersion, low attenuation, and with remarkable structural simplicity.
Abstract: Sources and systems for far-infrared or terahertz (1 THz = 10(12) Hz) radiation have received extensive attention in recent years, with applications in sensing, imaging and spectroscopy. Terahertz radiation bridges the gap between the microwave and optical regimes, and offers significant scientific and technological potential in many fields. However, waveguiding in this intermediate spectral region still remains a challenge. Neither conventional metal waveguides for microwave radiation, nor dielectric fibres for visible and near-infrared radiation can be used to guide terahertz waves over a long distance, owing to the high loss from the finite conductivity of metals or the high absorption coefficient of dielectric materials in this spectral range. Furthermore, the extensive use of broadband pulses in the terahertz regime imposes an additional constraint of low dispersion, which is necessary for compatibility with spectroscopic applications. Here we show how a simple waveguide, namely a bare metal wire, can be used to transport terahertz pulses with virtually no dispersion, low attenuation, and with remarkable structural simplicity. As an example of this new waveguiding structure, we demonstrate an endoscope for terahertz pulses.

1,047 citations

Journal ArticleDOI
19 Jul 2012-Nature
TL;DR: The observation of an insulator–metal transition in vanadium dioxide induced by a terahertz electric field is reported, demonstrating that integration of metamaterials with complex matter is a viable pathway to realize functional nonlinear electromagnetic composites.
Abstract: An innovative technique uses ultrafast below-bandgap electric-field pulses to induce and probe an insulator–metal transition in an oxide thin film on which a metamaterial structure has been deposited. The transition from insulating to metallic behaviour and the microscopic interactions that accompany the transition are important phenomena in electronic materials. Until now it has not been possible to observe the transition directly in a time-resolved manner. Here, Richard Averitt and colleagues use ultrafast terahertz pulses to induce a phase transition in a prototypical insulator–metal transition material (vanadium dioxide) on which a metamaterial structure has been deposited. The metamaterial serves to amplify the local terahertz field, as well as to detect macroscopic changes in vanadium dioxide. Through direct, time-resolved observations, the authors establish a detailed microscopic picture of the structural and electronic changes underlying the insulator–metal transition. They conclude that their technique is versatile and could even be used to study phase transitions in superconductors. Electron–electron interactions can render an otherwise conducting material insulating1, with the insulator–metal phase transition in correlated-electron materials being the canonical macroscopic manifestation of the competition between charge-carrier itinerancy and localization. The transition can arise from underlying microscopic interactions among the charge, lattice, orbital and spin degrees of freedom, the complexity of which leads to multiple phase-transition pathways. For example, in many transition metal oxides, the insulator–metal transition has been achieved with external stimuli, including temperature, light, electric field, mechanical strain or magnetic field2,3,4,5,6,7. Vanadium dioxide is particularly intriguing because both the lattice and on-site Coulomb repulsion contribute to the insulator-to-metal transition at 340 K (ref. 8). Thus, although the precise microscopic origin of the phase transition remains elusive, vanadium dioxide serves as a testbed for correlated-electron phase-transition dynamics. Here we report the observation of an insulator–metal transition in vanadium dioxide induced by a terahertz electric field. This is achieved using metamaterial-enhanced picosecond, high-field terahertz pulses to reduce the Coulomb-induced potential barrier for carrier transport9. A nonlinear metamaterial response is observed through the phase transition, demonstrating that high-field terahertz pulses provide alternative pathways to induce collective electronic and structural rearrangements. The metamaterial resonators play a dual role, providing sub-wavelength field enhancement that locally drives the nonlinear response, and global sensitivity to the local changes, thereby enabling macroscopic observation of the dynamics10,11. This methodology provides a powerful platform to investigate low-energy dynamics in condensed matter and, further, demonstrates that integration of metamaterials with complex matter is a viable pathway to realize functional nonlinear electromagnetic composites.

1,023 citations

Journal ArticleDOI
TL;DR: This work presents active optical control of metamaterial-induced transparency through active tuning of the dark mode, and opens up the possibility for designing novel chip-scale ultrafast devices that would find utility in optical buffering and terahertz active filtering.
Abstract: Recently reported metamaterial analogues of electromagnetically induced transparency enable a unique route to endow classical optical structures with aspects of quantum optical systems. This method opens up many fascinating prospects on novel optical components, such as slow light units, highly sensitive sensors and nonlinear devices. In particular, optical control of electromagnetically induced transparency in metamaterials promises essential application opportunities in optical networks and terahertz communications. Here we present active optical control of metamaterial-induced transparency through active tuning of the dark mode. By integrating photoconductive silicon into the metamaterial unit cell, a giant switching of the transparency window occurs under excitation of ultrafast optical pulses, allowing for an optically tunable group delay of the terahertz light. This work opens up the possibility for designing novel chip-scale ultrafast devices that would find utility in optical buffering and terahertz active filtering.

998 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
20232,476
20225,208
20212,507
20202,949
20193,338