Terasnap

Monday, March 30, 2015

Abstract- Plasmonic bandpass filter based on graphene nanoribbon

Plasmonic bandpass filter based on graphene nanoribbon


Huawei Zhuang, Fanmin Kong, Kang Li, and Shiwei Sheng  »View Author Affiliations
http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-54-10-2558
Applied Optics, Vol. 54, Issue 10, pp. 2558-2564 (2015)
http://dx.doi.org/10.1364/AO.54.002558

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A plasmonic bandpass filter based on graphene is proposed and numerically investigated using the finite-difference time-domain method. The proposed filter has a very simple structure, including two graphene nanoribbon waveguides laterally coupled to a graphene ribbon resonator. The transmission efficiency can be tuned by altering the coupling distance between the ribbons. At the same time, the variation of the transmission spectra is investigated by tuning the size of the graphene resonant ribbon. Notably, due to the unique electronic tunability of graphene, the transmission spectra can be freely tuned in a broad frequency range by choosing the chemical potential, which exhibits more flexible tunability than that used in conventional metallic devices. Attributed to the standing wave distribution of different modes excited in the graphene resonant ribbon, the proposed filter can be used for the plasmonic device with the capability of band selection or power splitting by locating the output waveguide ports in the suitable positions.
© 2015 Optical Society of America

Sunday, March 29, 2015

Abstract-Applications of Terahertz Wave Technology in Smart Textiles



The terahertz radiation bridges the gap between microwave and infrared light, which consists of electromagnetic waves with frequencies ranging from 100 GHz to 1,000 GHz. There are approximately one-half of the total luminosity and most of the photons emitted since the Big Bang fall into the terahertz frequency region. Terahertz spectroscopy and imaging are two important techniques for the applications to textiles, which are described in this chapter. Some terahertz spectroscopy experimental systems were presented, such as time-domain spectroscopy-based terahertz pulsed system and backward-wave oscillator-based continuous-wave terahertz system. Several applications of the terahertz spectroscopy technique were reviewed to textile identification and sensing, such as textile fibers, textile materials, and wool textiles. Terahertz imaging of object behind textile barriers was demonstrated and the images were segmented for target detection. Terahertz imaging applications to textiles were also reviewed, such as measuring textile water content, detecting target behind textile barriers, and testing composites nondestructively.

Friday, March 27, 2015

Abstract-Broadband molecular sensing with a tapered spoof plasmon waveguide



Broadband molecular sensing with a tapered spoof plasmon waveguide

Jingjing Yang, Yan Francescato, Dezhang Chen, Jianfeng Yang, and Ming Huang  »View Author Affiliations

Optics Express, Vol. 23, Issue 7, pp. 8583-8589 (2015)
http://dx.doi.org/10.1364/OE.23.008583
http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-23-7-8583
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Unambiguous identification of low concentration chemical mixtures can be performed by broadband enhanced infrared absorption (BEIRA). Here we propose and numerically study a corrugated parallel plate waveguide (CPPW) with gradient grooves which is capable of directly converting transmission modes to surface plasmon modes and could hence serve as a powerful chemical sensor. Such a waveguide can be designed to exhibit a wide pass band covering an extended portion of a molecule absorption spectrum. Broadband sensing of toluene and ethanol thin layers is demonstrated by calculating the transmission coefficient of the waveguide and is shown to correspond exactly to their infrared spectra. In addition, the upper limit and the lower limit of the bandgap are mainly dependent on the minimum and maximum groove height, respectively, which provide an effective way of tuning the working frequency of the device in order to support surface plasmon modes within a desired frequency range according to a specific application.
© 2015 Optical Society of America

Abstract-Exploiting the dispersion of the double-negative-index fishnet metamaterial to create a broadband low-profile metallic lens



Exploiting the dispersion of the double-negative-index fishnet metamaterial to create a broadband low-profile metallic lens

B. Orazbayev, V. Pacheco-Peña, M. Beruete, and M. Navarro-Cía  »View Author Affiliations
http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-23-7-8555
Optics Express, Vol. 23, Issue 7, pp. 8555-8564 (2015)
http://dx.doi.org/10.1364/OE.23.008555

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Metamaterial lenses with close values of permittivity and permeability usually display low reflection losses at the expense of narrow single frequency operation. Here, a broadband low-profile lens is designed by exploiting the dispersion of a fishnet metamaterial together with the zoning technique. The lens operates in a broadband regime from 54 GHz to 58 GHz, representing a fractional bandwidth ~7%, and outperforms Silicon lenses between 54 and 55.5 GHz. This broadband operation is demonstrated by a systematic analysis comprising Huygens-Fresnel analytical method, full-wave numerical simulations and experimental measurements at millimeter waves. For demonstrative purposes, a detailed study of the lens operation at two frequencies is done for the most important lens parameters (focal length, depth of focus, resolution, radiation diagram). Experimental results demonstrate diffraction-limited ~0.5λ transverse resolution, in agreement with analytical and numerical calculations. In a lens antenna configuration, a directivity as high as 16.6 dBi is achieved. The different focal lengths implemented into a single lens could be potentially used for realizing the front end of a non-mechanical zoom millimeter-wave imaging system.
© 2015 Optical Society of America

TeraView ships and delivers its first unit



http://www.ofcconference.org/en-us/home/news-and-press/exhibitor-press-releases/terapulse-4000-%E2%80%93-teraview-ships-and-delivers-its-f/

TeraView is pleased to announce that following launch the TeraPulse 4000 in February 2015, it has successfully installed a system at a world-leading research institute in France after winning a completive tender.
 
The system was provided to the Laboratoire Ondes et Matière d'Aquitaine (LOMA), a joined research unit of the University of Bordeaux  and CNRS (Le Centre National de la Recherche Scientifique). Professor Patrick Mounaix (patrick.mounaix@u-bordeaux.fr), who is the director of research at the Laboratoire IMS- UMR 5218 CNRS - Groupe Nano - Equipe Laser, Université Bordeaux, Bat A31,  has a long and distinguished track record in terahertz-related research, and will utilize the system for postal inspection in the framework of InPoSec (www.inposec.eu) joint project funded by ANR (Agence Nationale de la Recherche)  and BMBF(Federal Ministry of Education and Research). The TeraPulse was supplied with external fibres to provide a flexible configuration for different experimental set ups.
 
Based on TeraView’s decade of experience providing and supporting terahertz systems, TeraView’s proprietary software platform has been re-written and substantially enhanced based on customer feedback. The new software package fully integrates the spectroscopic and imaging capabilities of the unit into one common user interface.  The system can also be supplied with its own LABVIEW interface to allow customers to configure the software into their own applications.

Terahertz image of package containing drugs contained with an envelope. Courtesy of, Patrick Mounaix from the University of Bordeaux, 2015 (patrick.mounaix@u-bordeaux.fr)
 
Dr Don Arnone, TeraView’s CEO stated “We have received substantial interest in the TeraPulse 4000, and are delighted by the quick acceptance of the new system by our customers.  These initial orders re-enforce TeraView’s pre-eminent position as the partner of choice for terahertz customers, and also demonstrate a smooth transition to the next generation of our product. ”
 
TeraView also provides the industry’s largest range of proven, plug-and-play modules with proven functionality, performance and reliability in the field.  The TeraPulse 4000 and its reflection imaging module offer the best resolution for Terahertz imaging across a range of applications.


About TeraView
TeraView is the world’s first company devoted to the application of Terahertz light for spectroscopy and imaging. A spin out from the Toshiba Corporation and Cambridge University in 2001, the team at TeraView has been developing its technology and products across a number of applications for the last quarter of a century, and is now approaching 100 systems installed in circa 30 countries. TeraView provides both terahertz instrumentation as well as applications know-how to its customers, encompassed in over 100 peer-reviewed scientific publications as well as the largest collection of granted patents on terahertz technology. Headquartered in Cambridge, sales and support are available throughout Europe, North America and the Far East either directly or through a network of distributors.