Using technology to deliver cancer follow-up : a systematic review

Peer reviewedPublisher PD

Quadrupole-Quadrupole Interactions to Control Plasmon-Induced Transparency

Radiative dipolar resonance with Lorentzian line-shape induces the otherwise dark quadrupolar resonances resulting in electromagnetically induced transparency (EIT). The two interfering excitation pathways of the dipole are earlier shown to result in a Fano line shape with a high figure of merit suitable for sensing. In metamaterials made of metal nanorods or antennas, the plasmonic EIT (PIT) efficiency depends on the overlap of the dark and bright mode spectra as well as the asymmetry resulting from the separation between the monomer (dipole) and dimer (quadrupole) that governs the coupling strength. Increasing asymmetry in these structures leads to the reduction of the figure of merit due to a broadening of the Fano resonance. We demonstrate a PIT system in which the simultaneous excitation of two dipoles result in double PIT. The corresponding two quadrupoles interact and control the quality factor (Q) of the PIT resonance. We show an antiresonancelike symmetric line shape with nonzero asymmetry factors. The PIT resonance vanishes due to quadrupole-quadrupole coupling. A Q factor of more than 100 at 0.977 THz is observed, which is limited by the experimental resolution of 6 GHz. From polarization-dependent studies we show that the broadening of the Lorentzian resonance is due to scattering-induced excitation of orthogonally oriented dipoles in the monomer and dimer bars in the terahertz regime. The high Q factors in the terahertz frequency region demonstrated here are interesting for sensing application

Pattern and Peel method for fabricating mechanically tunable terahertz metasurface on an elastomeric substrate

In this article, we explore a mechanically tunable metasurface on an elastic polydimethylsiloxane (PDMS) membrane operating at Terahertz (THz) frequencies synthesized using a "pattern and peel fabrication" technique. The tunability of the metasurface is based on the change of physical dimensions of the individual micro-structures due to the strain caused by mechanical stretching. The novelty of this technique is the ability to use high resolution e-beam patterning in contrast to established screen-printing techniques reported in the literature. The metasurface studied in this article is a periodic lattice of split-ring structures resonant at THz frequencies. The effect of mechanical stretching on the response of the metasurface is investigated thoroughly through experiments and numerical simulations. The response of the metamaterial to stretching manifests as a shift in the higher order mode by similar to 12% for an applied strain of similar to 25%. This tunability of the spectral response with macroscopic strain is not only substantial for the given structure, but also follows a linear behavior. This device can have potential applications in communications technology, remote strain sensing, chemical and biological sensing. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen