Collaborations
Collaborations.UoBMKlemm History
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!! %newwin% [[http://www.bristol.ac.uk/engineering/people/maciej-klemm/index.html | Maciek Klemm]]\\
!! Centre for Communications Research, University of Bristol, UK\\\
!! Dielectric reflectarrays\\
In the past few years, important efforts have been deployed to find alternatives to on-chip, low-performance metal interconnects between devices. Because of the ever-increasing density of integrated components, intra- and inter-chip data communications have become a major bottleneck in the improvement of information processing. Given the compactness and the simple implantation of the devices, communications via free-space optics between nanoantenna-based arrays have recently drawn more attention. Here, we focus on a specific low-loss design of dielectric reflectarray (DRA), whose geometry is based on a periodic repartition of dielectric cylinders on a metallic plate. When illuminated in normal incidence, specific patterns of such resonators provide a constant phase gradient along the dielectric/metal interface, thus altering the phase of the incident wavefront. The gradient of phase shift generates an effective wavevector along the interface, which is able to deflect light from specular reflection. However, the flaws of the lithographic production process can lead to discrepancies between the ideal device and the actual resonator array. Here, we propose to exploit our DGTD solver to study the impact of the lithographic flaws on the performance of a 1D reflectarray. Efficient computations are obtained by combining high-order polynomial approximation with curvilinear meshing of the resonators, yielding accurate results on very coarse meshes. The study is continued with the
computation of the reflection of a 2D reflectarray.
(:table border='0' width='100%' align='center' cellspacing='1px':)
(:cellnr align='center':) %width=550px% http://www-sop.inria.fr/nachos/pics/collabs/m_klemm/bigdiel_sharp.png
(:cellnr align='center':) Ideal reflectarray
(:cellnr align='center':) %width=550px% http://www-sop.inria.fr/nachos/pics/collabs/m_klemm/bigdiel_imperfect.png
(:cellnr align='center':) Realistic reflectarray
(:tableend:)
%center% Ideal and realistic 1D dielectric reflectarray meshes. The red tetrahedra correspond to silver, while the green ones are made of an anisotropic dielectric material. The device is surrounded by air and terminated by a PML above and below, and by periodic boundary conditions on the lateral sides
(:table border='0' width='100%' align='center' cellspacing='1px':)
(:cellnr align='center':) %width=300px% http://www-sop.inria.fr/nachos/pics/collabs/m_klemm/bigdiel_ideal_f1.png
(:cell align='center':) %width=300px% http://www-sop.inria.fr/nachos/pics/collabs/m_klemm/bigdiel_imperfect_f1.png
(:cellnr align='center':) Ideal reflectarray
(:cell align='center':) Realistic reflectarray
(:tableend:)
%center% Time-domain snapshot of E'_y_' component for ideal and realistic 1D dielectric reflectarrays. Solution is obtained in established regime at t = 0.1 ps. Fields are scaled to [-1,1]
>><<
!! %newwin% [[http://www.bristol.ac.uk/engineering/people/maciej-klemm/index.html | Maciek Klemm]]\\
!! Centre for Communications Research, University of Bristol, UK\\\
!! Dielectric reflectarrays\\
In the past few years, important efforts have been deployed to find alternatives to on-chip, low-performance metal interconnects between devices. Because of the ever-increasing density of integrated components, intra- and inter-chip data communications have become a major bottleneck in the improvement of information processing. Given the compactness and the simple implantation of the devices, communications via free-space optics between nanoantenna-based arrays have recently drawn more attention. Here, we focus on a specific low-loss design of dielectric reflectarray (DRA), whose geometry is based on a periodic repartition of dielectric cylinders on a metallic plate. When illuminated in normal incidence, specific patterns of such resonators provide a constant phase gradient along the dielectric/metal interface, thus altering the phase of the incident wavefront. The gradient of phase shift generates an effective wavevector along the interface, which is able to deflect light from specular reflection. However, the flaws of the lithographic production process can lead to discrepancies between the ideal device and the actual resonator array. Here, we propose to exploit our DGTD solver to study the impact of the lithographic flaws on the performance of a 1D reflectarray. Efficient computations are obtained by combining high-order polynomial approximation with curvilinear meshing of the resonators, yielding accurate results on very coarse meshes. The study is continued with the
computation of the reflection of a 2D reflectarray.
(:table border='0' width='100%' align='center' cellspacing='1px':)
(:cellnr align='center':) %width=550px% http://www-sop.inria.fr/nachos/pics/collabs/m_klemm/bigdiel_sharp.png
(:cellnr align='center':) Ideal reflectarray
(:cellnr align='center':) %width=550px% http://www-sop.inria.fr/nachos/pics/collabs/m_klemm/bigdiel_imperfect.png
(:cellnr align='center':) Realistic reflectarray
(:tableend:)
%center% Ideal and realistic 1D dielectric reflectarray meshes. The red tetrahedra correspond to silver, while the green ones are made of an anisotropic dielectric material. The device is surrounded by air and terminated by a PML above and below, and by periodic boundary conditions on the lateral sides
(:table border='0' width='100%' align='center' cellspacing='1px':)
(:cellnr align='center':) %width=300px% http://www-sop.inria.fr/nachos/pics/collabs/m_klemm/bigdiel_ideal_f1.png
(:cell align='center':) %width=300px% http://www-sop.inria.fr/nachos/pics/collabs/m_klemm/bigdiel_imperfect_f1.png
(:cellnr align='center':) Ideal reflectarray
(:cell align='center':) Realistic reflectarray
(:tableend:)
%center% Time-domain snapshot of E'_y_' component for ideal and realistic 1D dielectric reflectarrays. Solution is obtained in established regime at t = 0.1 ps. Fields are scaled to [-1,1]
>><<