Actions for Hybrid metasurface for ultra-broadband terahertz modulation [electronic resource].

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Hybrid metasurface for ultra-broadband terahertz modulation [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 2014.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description
Article numbers 181,108 : digital, PDF file
Additional Creators
Los Alamos National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
We demonstrate an ultra-broadband free-space terahertz modulator based on a semiconductor-integrated metasurface. The modulator is made of a planar array of metal cut-wires on a silicon-on-sapphire substrate, where the silicon layer functions as photoconductive switches. Without external excitation, the cut-wire array exhibits a Lorentzian resonant response with a transmission passband spanning dc up to the fundamental dipole resonance above 2 THz. Under photoexcitation with 1.55 eV near-infrared light, the silicon regions in the cut-wire gaps become highly conductive, causing a transition of the resonant metasurface to a wire grating with a Drude response. In effect, the low-frequency passband below 2 THz evolves into a stopband for the incident terahertz waves. Experimental validations confirm a bandwidth of at least 100%, spanning 0.5 to 1.5 THz with -10 dB modulation depth. This modulation depth is far superior to -5 dB achievable from a plain silicon-on-sapphire substrate with effectively 25 times higher pumping energy. The proposed concept of ultra-broadband metasurface modulator can be readily extended to electrically controlled terahertz wave modulation.
Report Numbers
E 1.99:la-ur--14-27721
la-ur--14-27721
Subject(s)
Note
Published through SciTech Connect.
11/05/2014.
"la-ur--14-27721"
Applied Physics Letters 105 18 ISSN 0003-6951; APPLAB AM
Jane E. Heyes; Withawat Withayachumnankul; Nathaniel K. Grady; Dibakar Roy Chowdhury; Abul K. Azad; Hou-Tong Chen.
Funding Information
AC52-06NA25396
View MARC record | catkey: 24060130