SPIE Defense, Security and Defense meeting (23 - 27 April 2012)

TeraView customers present their recent research at the SPIE Defense, Security and Defense meeting 23 - 27 April 2012, Baltimore Convention Center Baltimore, Maryland United States

Terahertz properties of single-crystal  ferroelectric and dielectric materials  Paper 8363-5 of Conference 8363 Date: Monday, 23 April 2012 Author(s): S. K. Sundaram, New York State College of Ceramics at Alfred Univ. (United States); R. J. Koch, Alfred Univ. (United States); John S. McCloy, Pacific Northwest National Lab. (United States)
Abstract
Frequency dependence of complex permittivity of selected ferroelectric and dielectric single crystals and ceramics has been measured in the terahertz (THz) region using time-domain THz spectroscopy. This has been accomplished by measuring transmittance through the samples over a broad range of about 300 GHz to about 4THz in our laboratory. Samples include crystals of BaTiO3, SrTiO3, LiNbO3, LiTaO3, LaAlO3, and Bi4Ge3O12 and a polycrystalline ceramics of (PbMg1/3Nb2/3O3)0.73-(PbTiO3)0.27. We have compared our results with millimeter wave (MMW), RF, microwave, and optical frequency permittivities of these materials. Effects of crystallographic orientations on the dielectric properties have also been examined. Our results demonstrate that dielectric properties of these materials in the THz region correlate well with data obtained in other spectral regions, thereby expanding available data to a wider range of the electromagnetic spectrum. For TeraView's range of products see http://www.teraview.com/products/index.html for more information about  the Spectra 3000 spectrometer click here (http://www.teraview.com/products/terahertz-pulsed-spectra-3000/index.html) For more information information click here

Terahertz absorption spectra of benzene-1,2-diol, benzene-1,3-diol and benzene-1,4-diol

Chemical Physics Letters

Volumes 525–526, 16 February 2012, Pages 140–143

• Zhuan-Ping Zheng, 
• Wen-Hui Fan, 
• Hui Yan

Abstract

The terahertz spectra (8–128 cm⁻¹) of three structural isomers have been measured using terahertz time-domain spectroscopy at room temperature. Substantial differences among these THz spectra have been found and implied that THz-TDS is an excellent tool to identify isomers. Numerical calculation based on solid-state density functional theory has been carried out and assigned the observed THz features theoretically. Good agreement between the calculated and experimentally measured spectra for benzene-1,2-diol and benzene-1,3-diol has been achieved. According to the calculated results, it is found that the measured THz spectra of these two isomers mainly originate from intermolecular vibrations.

Molecular arrangement and crystal packing of benzene-1,2-diol, benzene-1,3-diol and benzene-1,4-diol. The left-hand panel is a view along the crystalline b axis, the mid- and the right-hand ones are the views along the crystallinec axis. The green and dashed lines show the hydrogen bonds between molecules in the unit cell. 

To read the full paper click here (http://www.sciencedirect.com/science/article/pii/S0009261411015739)

For more information about  the Spectra 3000 spectrometer click here

(http://www.teraview.com/products/terahertz-pulsed-spectra-3000/index.html)

Terahertz spectra of explosive materials

We have been asked for a reference for the terahertz spectra of explosive materials.


Below is a paper that was written a number of years ago been and is still of interest


The very far-infrared spectra of energetic materials and possible confusion materials using terahertz pulsed spectroscopy
Vibrational Spectroscopy 42(2)243-248(2006).
T. Lo, I.S. Gregory, C. Baker, P.F. Taday, W.R. Tribe, M.C. Kemp 

Abstract

We have measured the terahertz absorption spectra of 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), pentaerythritol tetranitrate (PETN), 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX), 2,4,6-trinitrotoluene (TNT), the plastic explosives Semtex H, SX2, and Metabel, and a number of confusion materials using terahertz pulsed transmission spectroscopy. Spectral fingerprints were obtained from 3 to 133 cm⁻¹. The spectra of the plastic explosives are dominated by the spectral signatures of their explosive components due to low frequency vibrations and crystalline phonon modes. Importantly, the terahertz spectra of the confusion materials show no resemblance to the explosives spectra. The refractive indices obtained for the plastic explosives and confusion materials allowed us to derive reflectance spectra, which appear distinct and so suggest that terahertz reflection spectroscopy is a suitable tool for the detection of concealed explosives in security applications.

The full paper can be found at http://www.sciencedirect.com/science/article/pii/S0924203106000439


For TeraView's range of products see http://www.teraview.com/products/index.html 

THz spectroscopy of explosive-related simulants and oxidizers

T. Trzcinski, N. Palka, M. Szustakowski

Institute of Optoelectronics, Military University of Technology, 2 Kaliski St., 00-908 Warsaw, Poland

Bulletin of the Polish Academy of Sciences: Technical Sciences 59(4),445-7 ( 2011) 

DOI 10.2478/v10175-011-0056-4

Abstract

In this paper we report on measurement of spectra of commonly applied explosives, some materials which can be used for manufacture of explosive and THz simulants of explosives in transmission mode. Substances were prepared as pellets, and the measurements were performed using the Time Domain Spectroscopy system in the range 0.1-3.0 THz.

From the paper

“... For Time Domain Spectroscopy measurement, Teraview TPS 3000 unit in transmission
configuration was used...”

For TeraView's range of products see http://www.teraview.com/products/index.html 

Where to publish?

Some people have asked where should they publish their terahertz work one recent addition to the publishing world is the IEEE Transactions on Terahertz Science and Technology.  Information about the journal can be found at http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=5503871 

AIMS AND SCOPE

IEEE Transactions on Terahertz Science and Technology is specifically aimed at the frequency range between 300 GHz and 10 THz – "Expanding the use of the Electromagnetic Spectrum.''

The transactions covers a wide range of activities and developments in terahertz science and applications, while at the same time helping to bridge the technology gap between the RF and photonics communities. The journal targets high impact papers with broad appeal to the rapidly expanding terahertz community. Although the journal is sponsored by the Microwave Theory and Techniques Society, the scope of the transactions extends to fields and activities that are outside of the traditional RF and microwave communities.

CONTACTS

EDITOR-IN-CHIEF

Peter H. Siegel

California Institute of Technology

Jet Propulsion Laboratory

4800 Oak Grove Drive

Pasadena, CA  91109  USA

phone: +1 (818) 354-9089

Fax: +1 (818) 393-4683

phs@caltech.edu

Managing Editor

Dylan Williams

National Institute of Standards and Technology

Boulder, CO  80305  USA

phone: +1 (303) 497 3138

Fax: +1 (303) 497 3970

dylan@boulder.nist.gov