Raji A Shankar

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Dynamically reconfigurable metasurfaces open up unprecedented opportunities in applications such as high capacity communications, dynamic beam shaping, hyperspectral imaging, and adaptive optics. The realization of high performance metasurface-based devices remains a great challenge due to very limited tuning ranges and modulation depths. Here we show that(More)
Complementary metal–oxide–semiconductor compatible athermal silicon nitride/titanium dioxide hybrid micro-ring resonators Appl. Application of zero-index metamaterials for surface plasmon guiding Appl. Photonic crystal coupled cavities with increased beaming and free space coupling efficiency Appl. Efficient coupler between silicon photonic and(More)
BACKGROUND Myeloid-related protein 8 (MRP8) and MRP14 are S100 family calcium binding proteins that form a heterodimer known as calprotectin or MRP8/14 that is present in the cytosol of neutrophils and monocytes. MRP8/14 becomes associated with endothelium at sites of monocyte and neutrophil adhesion and transmigration and induces a thrombogenic and(More)
Graphene is an attractive photoconductive material for optical detection due to its broad absorption spectrum and ultrashort response time. However, it remains a great challenge to achieve high responsivity in graphene detectors because of graphene's weak optical absorption (only 2.3% in the monolayer graphene sheet) and short photocarrier lifetime (<1 ps).(More)
We report the initial evaluation of a mid-infrared QCL-coupled silicon-on-sapphire ring resonator gas sensor. The device probes the N 2 O 2241.79 cm −1 optical transition (R23 line) in the ν 3 vibrational band. N 2 O concentration is deduced using a non-linear least squares fit, based on coupled-mode theory, of the change in ring resonator Q due to gas(More)
  • Martin Mittendorff, Josef Kamann, Jonathan Eroms, Dieter Weiss, Christoph Drexler, Sergey D Ganichev +196 others
  • 2015
Graphene has unique optical and electronic properties that make it attractive as an active material for broadband ultrafast detection. We present here a graphene-based detector that shows 40-picosecond electrical rise time over a spectral range that spans nearly three orders of magnitude, from the visible to the far-infrared. The detector employs a large(More)
Graphene is emerging as a broadband optical material which can be dynamically tuned by electrostatic doping. However, the direct application of graphene sheets in optoelectronic devices is challenging due to graphene's small thickness and the resultant weak interaction with light. By combining metal and graphene in a hybrid plasmonic structure, it is(More)
" I am persuaded that global climate change is one of the most important issues that we will face this century… " Florida Governor Charlie Crist " Let me state what the official IPCC prediction is: It (sea levels) could go up as much as three-quarters of a meter in this century, but there is a reasonable probability it could be much higher than that. " " A(More)
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