Spurious resonance suppression for a THz single bandpass filter using lossy glass substrates

Dongju Kim, Sung-Hwa Eo, Se-I Oh andJae-Hyung Jang



Abstract

Narrowband metamaterial-based filters using an array of split ring resonator (SRR) unit cells exhibit multiband operating characteristics due to the low frequency L-C resonance together with the high frequency dipole resonance of the SRR structure. To obtain single-band characteristics from the metamaterial-based terahertz (THz) band pass filter (BPF), the unwanted dipole resonance at high frequency should be suppressed. A lossy glass was used for a substrate for THz BPF that consists of a complementary split ring resonator (CSRR) to suppress the undesirable resonances at higher frequencies. The resulting CSRR filter on a glass substrate exhibited single-band BPF characteristics with a spurious band rejection ratio over 50 dB. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:58–60, 2015

This study was performed using TeraView's Spectra 3000 system. (TeraView, Cambridge, UK)

Full Article: http://onlinelibrary.wiley.com/doi/10.1002/mop.28775/full

Orbital-selective metal–insulator transition and gap formation above TC in superconducting Rb1−xFe2−ySe2

Zhe Wang, M. Schmidt, J. Fischer, V. Tsurkan, M. Greger, D. Vollhardt, A. Loidl & J. Deisenhofer



Abstract

Understanding the origin of high-temperature superconductivity in copper- and iron-based materials is one of the outstanding tasks of current research in condensed matter physics. Even the normal metallic state of these materials exhibits unusual properties. Here we report on a hierarchy of temperatures Tc<Tgap<Tmet in superconducting Rb1−xFe2−ySe2 observed by THz spectroscopy (Tc=critical temperature of the superconducting phase; Tgap=temperature below which an excitation gap opens; Tmet=temperature below which a metallic optical response occurs). Above Tmet=90 K the material reveals semiconducting characteristics. Below Tmet a coherent metallic THz response emerges. This metal-to-insulator-type, orbital-selective transition is indicated by an isosbestic point in the temperature dependence of the optical conductivity and dielectric constant at THz frequencies. At Tgap=61 K, a gap opens in the THz regime and then the superconducting transition occurs at Tc=32 K. This sequence of temperatures seems to reflect a corresponding hierarchy of the electronic correlations in different bands.

This study was performed using TeraView's Spectra 3000 system. (TeraView, Cambridge, UK)

Full Article: http://www.nature.com/ncomms/2014/140128/ncomms4202/full/ncomms4202.html

TeraView at OTST 2015

TeraView are happy to announce that TeraView's Dr. Philip Taday will be in attendance at the OTST 2015 conference in San Diego, California on the 8th - 13th of March 2015! 

"The sixth international workshop on Optical Terahertz Science and Technology (OTST 2015) will be held in San Diego, California, USA from March 8th - 13th, 2015. OTST is held every two years with the previous five conferences located in Orlando, Florida, USA (2005, 2007), Santa Barbara, California, USA (2009, 2011) and, most recently, Kyoto, Japan (2013). There have been exciting developments at terahertz frequencies in the past two years, and the goal of this conference is to bring together researchers from all over the world to discuss advances ranging from cutting edge sensing and detection to nonlinear dynamics in multifunctional materials. The talks and poster sessions will cover these advances with ample time for in-depth discussions amongst colleagues. In addition, on March 8th there will be an introductory workshop/tutorial for students and those who are new to the world of THz science and technology."

If you would like to arrange the opportunity for a meeting with Dr. Philip Taday you can contact him directly via: philip.taday@teraview.com 

TeraView will also be live tweeting from the event, so if you are at the event and would like to contact Dr. Philip Taday please do so via the TeraView Twitter account!

For more information on OTST 2015 visit: http://otst2015.ucsd.edu/

TeraPulse - The Next Generation Terahertz Spectrometer and Imaging System from TeraView

TeraView is pleased to announce the launch of its new Terahertz system, the TeraPulse 4000!


Building on the success of the TPS Spectra 3000 which has become the industry standard in Terahertz instrumentation, the TeraPulse 4000 offers the same industry leading performance and reliability, all within a single, compact unit. Smaller, lighter and more portable, the TeraPulse is equally at home in a laboratory or industrial environment.

The system is available with an on-board spectroscopy/imaging compartment (as shown above) or with fibres. The fibre based system can then accept various ’plug and play’ sample modules, enabling a range of different Terahertz applications that have been developed by TeraView over the last decade. Both configurations are fully compatible with TeraView’s existing and extensive range of “plug and play” modules, which allow users to quickly and economically expand their Terahertz capabilities.

The system is also supplied with a new software suite which fully integrates the improved spectroscopic and imaging capabilities of the unit into one common platform.

Dr Don Arnone, TeraView’s CEO stated “TeraPulse represents a substantial investment by TeraView in the future of Terahertz instrumentation, developed with extensive feedback from our customers around the world. It takes all of the reliability, stability and improved performance achieved over the last several years, and puts them into a smaller, lighter package with enhanced capabilities. The TeraPulse 4000 is designed to serve as a versatile core unit which can be configured for a variety of laboratory, production and other industrial applications. We are also planning other exciting additions to the TeraPulse range over the coming months, which come out of our continued commitment to R&D of Terahertz technology as well as close collaborations with our customers and partners. ”

To find out more please visit: www.teraview.com

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.

Diffusion and Swelling Measurements in Pharmaceutical Powder Compacts Using Terahertz Pulsed Imaging

Samy Yassin, Ke Su, Hungyen Lin, Lynn F. Gladden andJ. Axel Zeitler

Abstract

Tablet dissolution is strongly affected by swelling and solvent penetration into its matrix. A terahertz-pulsed imaging (TPI) technique, in reflection mode, is introduced as a new tool to measure one-dimensional swelling and solvent ingress in flat-faced pharmaceutical compacts exposed to dissolution medium from one face of the tablet. The technique was demonstrated on three tableting excipients: hydroxypropylmethyl cellulose (HPMC), Eudragit RSPO, and lactose. Upon contact with water, HPMC initially shrinks to up to 13% of its original thickness before undergoing expansion. HPMC and lactose were shown to expand to up to 20% and 47% of their original size in 24 h and 13 min, respectively, whereas Eudragit does not undergo dimensional change. The TPI technique was used to measure the ingress of water into HPMC tablets over a period of 24 h and it was observed that water penetrates into the tablet by anomalous diffusion. X-ray microtomography was used to measure tablet porosity alongside helium pycnometry and was linked to the results obtained by TPI. Our results highlight a new application area of TPI in the pharmaceutical sciences that could be of interest in the development and quality testing of advanced drug delivery systems as well as immediate release formulations. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci

This study was performed using TeraView's Spectra 3000 system. (TeraView, Cambridge, UK)

Full Article: http://onlinelibrary.wiley.com/doi/10.1002/jps.24376/full