14:35 : Passive Terahertz Compressive Imaging with Fano Resonances
Xuefeng Li, Xinya Bian, Bill Milne, Daping Chu
University of Cambridge (United Kingdom) We introduce a novel approach for terahertz compressive imaging with a single-pixel camera. Instead of actively switching sensing matrix, we utilize the source frequency (0.8-1.6 THz) as an index for various measurement masks. Using a systematic approach to engineer ultra-sharp Fano resonances, we are able to design an efficient passive metamaterial aperture for near perfect reconstruction. Such a device architecture could provide a new path for cost-effective THz imaging.
14:50 : Frequency selection in mid-IR quantum cascade lasers using built-in meta-surfaces of periodic nano-antennas
Tommaso Ongarello, Adel Bousseksou, Aloyse Degiron, Raffaele Colombelli
Paris Sud University (France) A meta-surface, consisting of a periodic array of linear nano-antennas, is implemented onto the top-surface of a mid-infrared quantum-cascade laser (QCL). The surface exhibits relatively narrow resonances, due to a collective diffractive response. Once implemented onto the QCL, mimicking a 2nd-order distributed feedback laser resonator, frequency selectivity is achieved with 1.5 percent of the laser surface covered by metal. The laser-antenna coupled-mode presents anomalous effective-index dispersion, demonstrating that the array acts as a meta-surface in a surface-emitting laser source.
15:05 : Metamaterial Antireflection Coating for Biological Tissues at Millimeter Waves
Helena Cano Garcia (1),Panagiotis Kosmas (1),Efthymios Kallos (2)
(1)King's College London (United Kingdom) , (2)Medical Wireless Sensing Ltd. - Metamaterial Technologies Inc. (United Kingdom) This paper presents simulation results of two different metamaterial-based antireflection coatings operating at millimeter waves. The first design minimizes the reflection from an acrylic slab and the second design minimizes the reflection from human skin. These designs achieve a reduction in the reflected power by 16 percent and 39 percent, respectively, at 60 GHz. The results open up the possibility of enhanced medical diagnostics using radio waves by reducing the EM impedance mismatch between the human skin and the surrounding environment.
15:20 : Quantum efficiency enhancement of a midwave infrared photodetector by coupling to surface plasmon polariton modes
Jill Nolde (1),M. Kim (2),Chul Kim (1),Eric Jackson (1),Chase Ellis (1),Joshua Abell (1),Orest Glembocki (1),Chadwick Canedy (1),Joseph Tischler (1),Igor Vurgaftman (1),Jerry Meyer (1),Edward Aifer (1)
(1)Naval Research Laboratory (USA) , (2)Sotera Defense Solutions, Inc. (USA) We demonstrated enhancement of the quantum efficiency (QE) of a thin InAsSb photodetector using a 1D plasmonic surface grating. The relation between grating period and enhancement wavelength is clearly shown as resonant dips in the measured grating reflectance and as peaks in the QE spectra. The QE and reflectance data are well matched to numerical simulations. From these results, we estimate a grating coupling efficiency of 34 percent.