Versatile and active THz wave polarization modulators using metamaterial/graphene resonators


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Authors
Zaman, AM 
Lu, Y 
Almond, NW 
Burton, OJ 
Alexander-Webber, J 
Abstract

jats:pActive modification of the polarization state is a key feature for the next-generation of wireless communications, sensing, and imaging in the THz band. The polarization modulation performance of an integrated metamaterial/graphene device is investigated jats:italicvia</jats:italic> a modified THz time domain spectroscopic system. Graphene’s Fermi level is modified through electrostatic gating, thus modifying the device’s overall optical response. Active tuning of ellipticity by jats:inline-formula<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m1">mml:mo></mml:mo></mml:math></jats:inline-formula>0.3 is reported at the resonant frequency of 0.80 THz. The optical activity of transmitted THz radiations is continuously modified by jats:inline-formula<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="m2">mml:mo></mml:mo>mml:mn21</mml:mn>mml:mo.</mml:mo>mml:msupmml:mrowmml:mn5</mml:mn></mml:mrow>mml:mrowmml:mtexto</mml:mtext></mml:mrow></mml:msup></mml:math></jats:inline-formula> at 0.71 THz. By carefully selecting the transmitted frequency with the relative angle between the incoming linear polarization and the device’s symmetry axis, active circular dichroism and optical activity are almost independently exploited. Finally, this all-electronically tuneable versatile polarization device can be used in all applications requiring an ultrafast modulation such as polarization spectroscopy, imaging, and THz wireless generation.</jats:p>

Description

Peer reviewed: True

Keywords
terahertz, metamaterials, graphene, wireless communications, integrated modulators
Journal Title
Frontiers in Nanotechnology
Conference Name
Journal ISSN
2673-3013
2673-3013
Volume Title
Publisher
Frontiers Media SA
Sponsorship
Engineering and Physical Sciences Research Council (EP/P021859/1)