Resonance enhancement of terahertz metamaterials by liquid crystals/indium tin oxide interfaces

Optics Express, March 2013, Vol. 21, Issue 5, pp. 6519-6525 (2013)
doi: 10.1364/OE.21.006519.

Authors: Zhen Liu, Chia-Yi Huang, Hongwei Liu, Xinhai Zhang, and Chengkuo Lee

Abstract

This work fabricates a terahertz (THz) metamaterial device, whose structure consists of split ring resonator array/ plastic substrate/ Indium Tin Oxide (ITO) film/ liquid crystals/ ITO film/ plastic substrate. Experiment results show that the resonance of the THz metamaterial device can be enhanced as voltage is applied to the liquid crystals. The enhancement will be more significant as higher voltage applied. The resonance enhancement is attributed to the fact that the liquid crystals/ITO interfaces exhibit the large difference in terms of refractive index between the two materials in THz regime. The interfaces reflect the incident electromagnetic wave and cause the reflected wave to enhance the resonance of the metamaterials. As those frequency-tunable metamaterial devices show different resonant transmittance at different frequencies, which is undesired, the liquid crystals/ITO interfaces can improve those frequency-tunable metamaterial devices with a constant transmittance at different frequencies.

... Figure 2 shows the transmission spectrums of the metamaterial device at applied voltages of 0
V, 4 V and 10 V. These spectrums are obtained by THz time-domain spectroscopy
(TeraView, TPS Spectra 3000) in transmission mode, where the non-polarized THz electromagnetic
wave as the probe light is normally incident to the metamaterial device from the side of the
SRR array...

More details at: http://www.opticsinfobase.org/oe/fulltext.cfm?uri=oe-21-5-6519&id=250680

 +The Optical Society (OSA)
OCIS codes: (160.3710) Liquid crystals; (160.3918) Metamaterials; (300.6495) Spectroscopy,
terahertz; (230.7408) Wavelength filtering devices.

Acknowledgments

This work was supported in part by SERC of the Agency for Science, Technology and Research (A*STAR) at the +National University of Singapore

Crystal engineering approach to produce complex of azelnidipine with maleic acid

Authors: Weiguang Lian ,  Dong Li ,  Min Wang ,  Caiqin Yang and Jing Wang
+RSC,CrystEngComm, 2013, Accepted Manuscript
DOI: 10.1039/C3CE26967A
Received 05 Dec 2012, Accepted 09 Mar 2013
First published on the web 12 Mar 2013

...THz spectra were acquired on TeraView's TPI spectra 1000 transmission spectrometer...

Abstract

A novel azelnidipine-maleic acid complex was prepared by the solvent-assisted cogrinding method. The obtained complex was characterized by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), infrared (IR), Raman, solid-state nuclear magnetic resonance (ssNMR), and terahertz (THz) spectroscopy. The PXRD and DSC measurement identified new different crystal form of the obtained complex other than those of the single azelnidipine and maleic acid. It was revealed that the azelnidipine-maleic acid complex was formed at a molar ratio of 2:1. IR, Raman and ssNMR spectroscopy verified that C-H...O hydrogen bond was formed between C=O from maleic acid and methyl group from azelnidipine. The distinctive THz spectrum showed that the vibrational mode of the complex was different from those of the starting materials, suggesting that THz spectroscopy is an ideal tool to evaluate complex formation. The solubilities of azelnidipine in maleic acid with different concentrations at different temperatures were investigated; the obtained values were used to calculate the formation constants and thermodynamic parameters. The improved dissolution rate in vitro of the complex showed potential to improve the physicochemical properties of azelnidipine API by crystal engineering approach.


More info at: http://pubs.rsc.org/en/content/articlelanding/2013/ce/c3ce26967a

University of Arkansas to Use TeraView's Terahertz System for Medical and Biological Imaging and Nanomaterial Characterization Research

+TeraView has supplied a state-of-the-art terahertz imaging system to the University of Arkansas. The TPS Spectra 3000 will expand the use of terahertz radiation in a variety of research fields like breast cancer imaging and the fabrication of nanoscale materials.

In 2012, the National Science Foundation has awarded Magda El-Shenawee, Principal Investigator, professor of electrical engineering, a new terahertz imaging and spectroscopy system to conduct cutting edge research at the University of Arkansas. Co-investigators are Greg Salamo, distinguished professor of physics, and Steve Stephenson, research professor in biological sciences, at the University of Arkansas; Robert Griffin, professor of radiation oncology at the University of Arkansas for Medical Sciences; and Gilbert Pacey, senior research scientist at IDCAST CBRNE and THz.

Dr. El-Shenawee will use the system to expand the understanding and applications of terahertz imaging in medical research. “Among many important applications, this system will allow us to continue our work on developing a non-hazardous and non-invasive imaging system for breast-cancer,” said Dr. El-Shenawee. “Because of the unique properties of terahertz light, the system will help reduce cancer recurrence by contributing to the thermal ablation of tumors.” Terahertz pulsed imaging (TPI™) provides good contrast between different types of soft tissue, and is a sensitive means of detecting the degree of water content as well as other markers of cancer and other diseases. “The major advantage of the system is that it allows measurements to be taken without destroying the sample material in the process,” said Dr. Stephenson.

In addition, the TPS Spectra 3000 will help researchers investigate the terahertz properties of novel functional materials. Dr. Salamo, expert in the field of semiconductor nanostructures at the Institute for Nanoscience and Engineering, will utilise terahertz radiation and imaging techniques to guide the fabrication of nano-acoustic imaging materials and devices.

COST TERA-MIR (Action MP 1204) - Call for STSMs Application

1st Call for Applications 2013 - Short-Term Scientific Missions (STSMs) within the TERA-MIR (MP 1204) network

Call opening: 14 March 2013
Call closure: 13 April 2013
Decision and notification: 30 April 2013

Please download the file with instructions and templates by visiting the website:
www.tera-mir.org/main/1st_STSMcall

COST MPNS Action MP1204

The main objective of this action is to advance novel materials, concepts and device designs for generating and detecting THz (0.3 THz to 10 THz) and Mid Infrared (10 THz to 100 THz) radiation using semiconductor, superconductor, metamaterials and lasers and to beneficially exploit their common aspects within a synergetic approach. 

Action Domain: Materials, Physics and Nanosciences (MPNS)
The Domain Materials, Physics and Nanosciences (MPNS) is home to material science, extending from conception through to production and includes characterization, examination, evaluation, fabrication and development, to actual application and service, as well as related databases, codes, standards and inspections.

The Domain thus also incorporates nanomaterials and nanosciences and the nanotechnological applications thereof. It also supports exploratory basic and applied research in physics, theoretical and experimental, as a key to understanding the laws governing the behaviour of matter and energy.

Useful links:
Official COST website
COST Action MP1204 on the official COST website
MPNS domain on the official COST website

School of Photonics 2013 - May 20–24, Cortona, Italy

The objective of this year school is to offer a wide perspective on those rapidly expanding areas of photonic research which are developing concepts and ideas closely related to electronic technologies. The link could be at the fundamental physics level, or in the chosen materials, or in the device implementations.
Topics:

1. Plasmonics
2. Terahertz technologies
3. Graphene photonics
4. Silicon photonics
5. Circuit electrodynamics
6. Metamaterials

The School will feature a number of lessons from leading international scientists of the respective fields and is open to Ph.D. and graduating students, as well as to junior Post-Docs. Participants are all encouraged to submit abstracts of their own research to be presented as posters and in a few selected orals.
Attendance is limited to 60 participants of which 30 places have been reserved for our ACTION students and Early Stage Researchers. Due to time constraints, the first 30 registered within the ACTION will be considered for financial support!

http://web.nano.cnr.it/scuolafotonica2013/

Graham Hibberd joins TeraView as Head of Business Development for the Analytical Business

+TeraView is pleased to announce the addition of +Graham Hibberd to its team as Head of Analytical Business Development.

Graham has over fourteen years of experience in sales and business development, with a heavy emphasis on the scientific research and measurement industry. He comes to TeraView from Formulatrix, where he held the position of Head of European Sales. Previously, Graham served as a Product Specialist at Varian and +Agilent Technologies where he was responsible for instrument sales of in the area of atomic absorption spectrometry and plasma mass spectrometry.

"I am extremely pleased to have Graham join our team," said +Ian Grundy, SVP Global Sales and Marketing. "The Analytical market is a key growth area for TeraView and I see Graham’s substantial experience in the field as being instrumental in helping us to continue this trend”.