Polyvinylidene Fluoride-Based Metasurface for High-Quality Active Switching and Spectrum Shaping in the Terahertz G-Band

We report theoretical investigations performed in the terahertz G-band, in the 228–232 GHz spectral window for a piezoelectrically-responsive ring-cone element metasurface composed of polyvinylidene fluoride (PVDF)/Silicon and PVDF/Silica glass. The choosing of this spectral window is motivated by a multitude of applications in terahertz detection and terahertz imaging, that commonly make use of this band. The uniqueness of the envisioned architecture resides in the combination between the readily-available polyvinylidene fluoride polymer and silicon/silica glass substrates, together with the introduction of an extra degree of freedom, in the form of a ring-cone architecture , and the active control of the geometric sizes through the longitudinal piezoelectric effect exhibited by the polymer. The spectral response of the metasurface is dependent on the combination between the polymer elements and the substrate, and ranges from near-zero absorption switching to a resonant behavior and significant absorption. The interaction between the electromagnetic field and the polymer-based metasurface also modifies the phase of the reflected and transmitted waves over a full 2π range, permitting complete control of the electric field polarization. Moreover, we take advantage of the longitudinal piezoelectric effect of PVDF and analyze the spectrum shaping capability of the polymer-based metasurface. Our analysis highlights the capability of the proposed architecture to achieve complete electric field polarization control, near-zero optical switching and resonant behavior, depending on the geometries and sizes of the architecture elements resulting from construction considerations and from the externally applied voltages through the piezoelectric effect.

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Investigation of microstructure and mechanical properties of polyvinylidene fluoride/carbon nanotube composites after electric field polarization: A molecular dynamics study

Computational Materials Science ◽

10.1016/j.commatsci.2018.03.021 ◽

2018 ◽

Vol 149 ◽

pp. 217-229 ◽

Cited By ~ 1

Author(s):

Hui-Lung Chen ◽

Shin-Pon Ju ◽

Chen-Yun Lin ◽

Cheng-Tang Pan

Keyword(s):

Mechanical Properties ◽

Molecular Dynamics ◽

Carbon Nanotube ◽

Electric Field ◽

Polyvinylidene Fluoride ◽

Field Polarization ◽

Microstructure And Mechanical Properties ◽

Nanotube Composites ◽

Electric Field Polarization ◽

Carbon Nanotube Composites

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Remote sensing of a NTC radio source from a Cluster tilted spacecraft pair

Annales Geophysicae ◽

10.5194/angeo-31-2097-2013 ◽

2013 ◽

Vol 31 (11) ◽

pp. 2097-2121 ◽

Cited By ~ 4

Author(s):

P. M. E. Décréau ◽

S. Kougblénou ◽

G. Lointier ◽

J.-L. Rauch ◽

J.-G. Trotignon ◽

...

Keyword(s):

Electric Field ◽

Circular Polarization ◽

Source Region ◽

Plane Waves ◽

Geomagnetic Latitude ◽

Magnetic Activity ◽

Spectral Signature ◽

Time Interval ◽

Field Polarization ◽

Electric Field Polarization

Abstract. The Cluster mission operated a "tilt campaign" during the month of May 2008. Two of the four identical Cluster spacecraft were placed at a close distance (~50 km) from each other and the spin axis of one of the spacecraft pair was tilted by an angle of ~46°. This gave the opportunity, for the first time in space, to measure global characteristics of AC electric field, at the sensitivity available with long boom (88 m) antennas, simultaneously from the specific configuration of the tilted pair of satellites and from the available base of three satellites placed at a large characteristic separation (~1 RE). This paper describes how global characteristics of radio waves, in this case the configuration of the electric field polarization ellipse in 3-D-space, are identified from in situ measurements of spin modulation features by the tilted pair, validating a novel experimental concept. In the event selected for analysis, non-thermal continuum (NTC) waves in the 15–25 kHz frequency range are observed from the Cluster constellation placed above the polar cap. The observed intensity variations with spin angle are those of plane waves, with an electric field polarization close to circular, at an ellipticity ratio e = 0.87. We derive the source position in 3-D by two different methods. The first one uses ray path orientation (measured by the tilted pair) combined with spectral signature of magnetic field magnitude at source. The second one is obtained via triangulation from the three spacecraft baseline, using estimation of directivity angles under assumption of circular polarization. The two results are not compatible, placing sources widely apart. We present a general study of the level of systematic errors due to the assumption of circular polarization, linked to the second approach, and show how this approach can lead to poor triangulation and wrong source positioning. The estimation derived from the first method places the NTC source region in the dawn sector, at a large L value (L ~ 10) and a medium geomagnetic latitude (35° S). We discuss these untypical results within the frame of the geophysical conditions prevailing that day, i.e. a particularly quiet long time interval, followed by a short increase of magnetic activity.

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