scholarly journals Coupling terahertz radiation between sub-wavelength metal-metal waveguides and free space using monolithically integrated horn antennae

2009 ◽  
Vol 17 (20) ◽  
pp. 18387 ◽  
Author(s):  
J. Lloyd-Hughes ◽  
G. Scalari ◽  
A. van Kolck ◽  
M. Fischer ◽  
M. Beck ◽  
...  
Keyword(s):  
Terahertz Radiation ◽  
Free Space ◽  
Monolithically Integrated ◽  
Metal Metal ◽  
Horn Antennae ◽  
Sub Wavelength

scholarly journals Controlling Refraction Using Sub-Wavelength Resonators

2018 ◽  
Vol 8 (10) ◽  
pp. 1942
Author(s):  
Yue Chen ◽  
Robert Lipton
Keyword(s):  
Frequency Dependence ◽  
Free Space ◽  
Near Infrared ◽  
Center Frequency ◽  
Negative Index ◽  
Index Properties ◽  
Frequency Bands ◽  
Transmitted Signal ◽  
Sub Wavelength

We construct metamaterials from sub-wavelength nonmagnetic resonators and consider the refraction of incoming signals traveling from free space into the metamaterial. We show that the direction of the transmitted signal is a function of its center frequency and bandwidth. The directionality of the transmitted signal and its frequency dependence is shown to be explicitly controlled by sub-wavelength resonances that can be calculated from the geometry of the sub-wavelength scatters. We outline how to construct a medium with both positive and negative index properties across different frequency bands in the near infrared and optical regime.

Magnetic modulation of Fano resonances in optically thin terahertz superlattice metasurfaces

2021 ◽  
Author(s):  
Subhajit Karmakar ◽  
Ravi Varshney ◽  
Dibakar Roy Chowdhury
Keyword(s):  
Magnetic Field ◽  
Free Space ◽  
Skin Depth ◽  
Electromagnetic Energy ◽  
Magnetic Control ◽  
Fano Resonances ◽  
Electromagnetic Responses ◽  
On Chip ◽  
Magneto Resistance ◽  
Sub Wavelength

Abstract Optically thin metasurfaces operating at sub-skin depth thicknesses are intriguing because of its associated low plasmonic losses (compared to optically thick, beyond skin-depth metasurfaces). However, their applicability has been restricted largely because of reduced free space coupling with incident radiations resulting in limited electromagnetic responses. To overcome such limitations, we propose enhancement of effective responses (resonances) in sub-skin depth metasurfaces through incorporation of magneto-transport (Giant Magneto Resistance, GMR) concept. Here, we experimentally demonstrate dynamic magnetic modulation of structurally asymmetric metasurfaces (consisting of superlattice arrangement of thin (~ 10 nm each) magnetic (Ni)/ nonmagnetic (Al) layers) operating at terahertz (THz) domain. With increasing magnetic field (applied from 0 to 30 mT approximately, implies increasing superlattice conductivity), we observe stronger confinement of electromagnetic energy at the resonances (both in dipole and Fano modes). Therefore, this study introduces unique magnetically reconfigurable ability in Fano resonant THz metamaterials, which directly improves its performances operating in the sub-skin depth regime. Our study can be explained by spin-dependent terahertz magneto-transport phenomena in metals and can stimulate the paradigm for on-chip spin-based photonic technology enabling dynamic magnetic control over compact, sub-wavelength, sub-skin depth metadevices.

scholarly journals Terahertz Field Confinement in Nonlinear Metamaterials and Near-Field Imaging

Photonics ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 22 ◽  
Author(s):  
George Keiser ◽  
Pernille Klarskov
Keyword(s):  
Terahertz Radiation ◽  
Terahertz Spectroscopy ◽  
Near Field ◽  
Terahertz Imaging ◽  
Imaging Systems ◽  
Near Field Imaging ◽  
Nonlinear Metamaterials ◽  
Terahertz Devices ◽  
Field Imaging ◽  
Sub Wavelength

This article reviews recent advances in terahertz science and technology that rely on confining the energy of incident terahertz radiation to small, very sub-wavelength sized regions. We focus on two broad areas of application for such field confinement: metamaterial-based nonlinear terahertz devices and terahertz near-field microscopy and spectroscopy techniques. In particular, we focus on field confinement in: terahertz nonlinear absorbers, metamaterial enhanced nonlinear terahertz spectroscopy, and in sub-wavelength terahertz imaging systems.

scholarly journals Amplifiers of free-space terahertz radiation

Optica ◽  
2017 ◽  
Vol 4 (7) ◽  
pp. 713 ◽  
Author(s):  
Tsung-Yu Kao ◽  
John L. Reno ◽  
Qing Hu
Keyword(s):  
Terahertz Radiation ◽  
Free Space
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