The 8th International Symposium on Terahertz Nanoscience (TeraNano 8)

The 8th International Symposium on Terahertz Nanoscience (TeraNano 8) will be held  at Okayama Convention Center, Okayama, Japan, during 19 November (Sunday) to 23 November (Thursday) in 2017. With the success of the first seven meetings of this series, held in Osaka, Okinawa, Honolulu, Osaka, Martinique, Okinawa, and Porquerolles, this symposium will bring together world leaders and young researchers and students working in the multi-disciplinary field of terahertz (THz) dynamics in nanostructures. This symposium provides a forum for the exchange of information on the basic science, technology, and applications of THz waves.  Although it will cover all aspects of THz science and technology, we will emphasize the advantages of combining the interdisciplinary domains of nanotechnology and THz technology, especially the field of THz science in nanomaterials and nanodevices. The conference will place special emphasis on international collaborations in research and education in this highly interdisciplinary and increasingly global field. Invited talks on current status and future prospects by leading researchers will be given as well as some contributed oral presentations. Moreover, this symposium will be held in combination with the 4th International Symposium on Microwave/Terahertz Science and Applications (MTSA 2017). This symposium will also place special emphasis on international exchanges for students and young researchers in this highly interdisciplinary fields. for more information see http://www.ile.osaka-u.ac.jp/research/thp/TeraNano8/

Calculation and Study of Graphene Conductivity Based on Terahertz Spectroscopy

Feng, X., Hu, M., Zhou, J., & Liu, S. (2017). Calculation and Study of Graphene Conductivity Based on Terahertz Spectroscopy. Journal of Infrared, Millimeter, and Terahertz Waves, 1-11.


Abstract

Based on terahertz time-domain spectroscopy system and two-dimensional scanning control system, terahertz transmission and reflection intensity mapping images on a graphene film are obtained, respectively. Then, graphene conductivity mapping images in the frequency range 0.5 to 2.5 THz are acquired according to the calculation formula. The conductivity of graphene at some typical regions is fitted by Drude-Smith formula to quantitatively compare the transmission and reflection measurements. The results show that terahertz reflection spectroscopy has a higher signal-to-noise ratio with less interference of impurities on the back of substrates. The effect of a red laser excitation on the graphene conductivity by terahertz time-domain transmission spectroscopy is also studied. The results show that the graphene conductivity in the excitation region is enhanced while that in the adjacent area is weakened which indicates carriers transport in graphene under laser excitation. This paper can make great contribution to the study on graphene electrical and optical properties in the terahertz regime and help design graphene terahertz devices.

for full paper see https://link.springer.com/article/10.1007/s10762-017-0362-5

... Terahertz transmission and reflection time domain signals (TDS) are obtained with a THz Spectroscope(TPS 3000 assembled by the British company TeraView Ltd) by means of a two- dimensional raster scanning on the graphene/quartz sample in 0.1 mm steps between the ...

Science Park workshop to explore new developments in Terahertz technology.

New developments, ideas and solutions in the fields of terahertz technology will be explored in a one-day workshop which takes place at Thornton Science Park later this month.

The Terahertz (THz) band is defined as the electromagnetic frequency domain spanning from 0.1 to 10 THz (a Terahertz is a unit of frequency equal to one trillion hertz). It has shown attractive applications in materials science, chemistry, communication engineering and the life sciences. As well as looking at the progress particularly made in the materials discipline, academics will be covering the broad applications of Terahertz (THz) technology in materials industries such as glassy, crystalline and dielectric relaxor materials (which are for future high speed memory storage). 

The workshop is being sponsored by the EPSRC’s (Engineering and Physical Sciences Research Council’s) Teranet fund. Event organiser Dr Bin Yang, Senior Lecturer in the Department of Electronic and Electrical Engineering, said: “Very little systematic research has been done in exploring the intrinsic mechanisms between the microstructure of materials and Terahertz (THz) properties. Our workshop will be of interest to academics and industrial experts alike, and will provide opportunities for collaboration between academia and industry. We hope that by bringing people together, we inspire new ideas and solutions for new functional THz materials or improvements to current materials research methods.” 

The workshop takes place on Wednesday April 26 between 9.20am and 4.30pm. It takes place at the University of Chester’s Thornton Science Park. It is free to attend but, as Thornton is a secure site, booking is essential. Please visit http://teraherzandmaterials.fse.network/index.html or email Rachel Roberts on r.roberts@chester.ac.uk to book a space.

Contrast in Terahertz Images of Archival Documents—Part II: Influence of Topographic Features

Bardon, T., May, R. K., Taday, P. F., & Strlič, M. (2017). Contrast in Terahertz Images of Archival Documents—Part II: Influence of Topographic Features. Journal of Infrared, Millimeter, and Terahertz Waves, 38(4), 467-482.

Abstract

We investigate the potential of terahertz time-domain imaging in reflection mode to reveal archival information in documents in a non-invasive way. In particular, this study explores the parameters and signal processing tools that can be used to produce well-contrasted terahertz images of topographic features commonly found in archival documents, such as indentations left by a writing tool, as well as sieve lines. While the amplitude of the waveforms at a specific time delay can provide the most contrasted and legible images of topographic features on flat paper or parchment sheets, this parameter may not be suitable for documents that have a highly irregular surface, such as water- or fire-damaged documents. For analysis of such documents, cross-correlation of the time-domain signals can instead yield images with good contrast. Analysis of the frequency-domain representation of terahertz waveforms can also provide well-contrasted images of topographic features, with improved spatial resolution when utilising high-frequency content. Finally, we point out some of the limitations of these means of analysis for extracting information relating to topographic features of interest from documents.

For information about the group see https://iris.ucl.ac.uk/iris/browse/profile?upi=MSTRL90

For full paper see https://link.springer.com/article/10.1007/s10762-016-0352-z

The group used a TeraView TPS 3000 terahertz spectrometer for this research

also see http://www.azom.com/suppliers.aspx?SupplierID=12145

Art Painting Diagnostic Before Restoration with Terahertz and Millimeter Waves

Guillet, J. P., Roux, M., Wang, K., Ma, X., Fauquet, F., Balacey, H., ... & Mounaix, P. (2017). Art Painting Diagnostic Before Restoration with Terahertz and Millimeter Waves. Journal of Infrared, Millimeter, and Terahertz Waves, 38(4), 369-379.

Abstract

Art painting diagnostic is commonly performed using electromagnetic waves at wavelengths from terahertz to X-ray. These former techniques are essential in conservation and art history research, but they could be also very useful for restoring artwork. While most studies use time domain imaging technique, in this study, a painting has been investigated using both time domain imaging (TDI) and frequency-modulated continuous wave (FMCW) system in the millimeter frequency range. By applying these systems to a painting of the eighteenth century, we detect and analyze the structure of some defects. This study underlines the differences between FMCW and TDI. We present the advantages and disadvantages of each technique on a real artwork.


for full paper see https://link.springer.com/article/10.1007/s10762-017-0358-1

The group used a TeraView TPS 3000 terahertz spectrometer

also see

http://www.azom.com/suppliers.aspx?SupplierID=12145

for more information about Patrick see https://www.linkedin.com/in/patrick-mounaix-22a59b46/?ppe=1

NIH/NCI Grant Will Further Investigation of Breast Tumor Margin Assessment

The National Cancer Institute, part of the National Institutes of Health, has awarded a three-year, $424,081 grant to Magda El-Shenawee, electrical engineering professor, for her work on an intraoperative and rapid method of detecting positive cancer margins during conservative breast cancer surgery, or lumpectomy.

Standard medical imaging techniques insufficiently provide clear assessment of breast tissue margins, resulting in a reported second surgery rate of 20 to 40 percent.

The grant will allow El-Shenawee's research team to advance the assessment of breast tumor margins using new Terahertz imaging technology, which will provide the groundwork for fast, intraoperative tumor margin assessment and significantly reduce the occurrence of second surgeries, cancer reoccurrence and metastasis.

Investigators will image two types of tumor tissues. Pictured above, are samples of freshly excised tumors from mice.

Bowman demonstrates how images can be viewed using terahertz imaging.

"When we talk to any doctor about the tumor margins, they see issues," said El-Shenawee. "If they can't get all of the tumor in the first operation, two things can occur. Cancer can come back in the same spot, or the cancer can metastasize and spread to other organs. That is the danger of breast cancer."

Terahertz technology offers high, sub-millimeter resolution, as well as sensitivity to water content, which can be a major contrast factor in biological tissues. The researchers will focus their efforts on imaging two types of tumor tissues - one developed from phantom tissues that mimic freshly excised human tumors and the other freshly excised tumors grown in mice.

"We believe this new Terahertz technology will give us better images of the tissue than current, standard methods," El-Shenawee said.

El-Shenawee will collaborate with University of Arkansas professors Narasimhan Rajaram, assistant professor of biomedical engineering; Jingxian Wu, associate professor of electrical engineering, Avishek Chakraborty, assistant professor of mathematical sciences; and Tyler Bowman, doctoral student in electrical engineering. Bowman is an NSF Graduate Fellow and University of Arkansas Distinguished Doctoral Fellow. El-Shenawee will also collaborate with Keith Bailey, director of the Oklahoma Animal Disease Diagnostic Laboratory at Oklahoma State University; and with Lucas Campbell, M.D., pathologist at Northwest Arkansas Pathology Associates in Fayetteville.

CONTACTS

Magda El-Shenawee, professor 
Department of Electrical Engineering 
479-575-4037, magda@uark.edu

Matt McGowan, science and research communications officer 
University Relations 
479-575-4246, dmcgowa@uark.edu

Sierra Mendoza, administrative specialist 
Department of Electrical Engineering 
479-575-3005, smendoza@uark.edu

also see

http://www.azom.com/suppliers.aspx?SupplierID=12145

Terahertz Superresolution Stratigraphic Characterization of Multilayered Structures Using Sparse Deconvolution

Dong, J., Wu, X., Locquet, A., & Citrin, D. S. (2017). Terahertz Superresolution Stratigraphic Characterization of Multilayered Structures Using Sparse Deconvolution. IEEE Transactions on Terahertz Science and Technology.

Abstract:

Terahertz sparse deconvolution based on an iterative shrinkage algorithm is presented in this study to characterize multilayered structures. With an upsampling approach, sparse deconvolution with superresolution is developed to overcome the time resolution limited by the sampling period in the measurement and increase the precision of the estimation of echo arrival times. A simple but effective time-domain model for describing the temporal pulse spreading due to the frequency-dependent loss is also designed and introduced into the algorithm, which greatly improves the performance of sparse deconvolution in processing time-varying pulses during the propagation of terahertz waves in materials. Numerical simulations and experimental measurements verify the algorithms and show that sparse deconvolution can be considered as an effective tool for terahertz nondestructive characterization of multilayered structures.

For full paper see http://ieeexplore.ieee.org/abstract/document/7874211/

... A standard THz time-domain spectroscopy system (Teraview TPS Spectra 3000) is employed in this study to perform THz reflective imaging at almost normal incidence on these two samples.......

For more information see https://www.ece.gatech.edu/faculty-staff-directory/david-s-citrin

For more information about  TeraView see http://www.azom.com/suppliers.aspx?SupplierID=12145

Mathematical Modelling of Liquid Transport in Swelling Pharmaceutical Immediate Release Tablets

Markl, D., Yassin, S., Wilson, D. I., Goodwin, D. J., Anderson, A., & Zeitler, J. A. (2017). Mathematical Modelling of Liquid Transport in Swelling Pharmaceutical Immediate Release Tablets. International Journal of Pharmaceutics.

Abstract

Oral dosage forms are an integral part of modern health care and account for the majority of drug delivery systems. Traditionally the analysis of the dissolution behaviour of a dosage form is used as the key parameter to assess the performance of a drug product. However, understanding the mechanisms of disintegration is of critical importance to improve the quality of drug delivery systems. The disintegration performance is primarily impacted by the hydration and subsequent swelling of the powder compact. Here we compare liquid ingress and swelling data obtained using terahertz pulsed imaging (TPI) to a set of mathematical models. The interlink between hydration kinetics and swelling is described by a model based on Darcy's law and a modified swelling model based on that of Schott. Our new model includes the evolution of porosity, pore size and permeability as a function of hydration time. Results obtained from two sets of samples prepared from pure micro-crystalline cellulose (MCC) indicate a clear difference in hydration and swelling for samples of different porosities and particle sizes, which are captured by the model. Coupling a novel imaging technique, such as TPI, and mathematical models allows better understanding of hydration and swelling and eventually tablet disintegration.

for full paper see 

http://www.sciencedirect.com/science/article/pii/S037851731730296X

for information about TeraView see
http://www.azom.com/suppliers.aspx?SupplierID=12145

for information about the Cambridge Terahertz group see
http://thz.ceb.cam.ac.uk/

Intermolecular anharmonicity in molecular crystals: interplay between experimental low-frequency dynamics and quantum quasi-harmonic simulations of solid purine

Ruggiero, Michael T., J. Axel Zeitler, and Alessandro Erba. "Intermolecular anharmonicity in molecular crystals: interplay between experimental low-frequency dynamics and quantum quasi-harmonic simulations of solid purine." Chemical Communications (2017).


Abstract

The intermolecular anharmonic potential of crystalline purine is probed by means of temperature-dependent terahertz time-domain spectroscopy, low-frequency Raman scattering, X-ray diffraction, and ab initio quasi-harmonic quantum-chemical simulations. As temperature increases, anharmonicity in the intermolecular interactions results in strongly anisotropic thermal expansion – with a negative thermal expansion along the b crystallographic axis – yielding corresponding bulk structural modifications. The observed thermally-induced shifts of most vibrational bands in the terahertz region of the spectra are shown to arise from volume-dependent thermal changes of the hydrogen-bond pattern along the a and b crystallographic axes.

Dr Zeilter's group uses a TeraPulse 4000 for more information see http://www.azom.com/equipment-details.aspx?EquipID=4411

Non-contact paint thickness measurement system for industrial deployment

Abstract

We present a non-contact, multi-layer coating thickness sensor based on the use of pulsed terahertz light.

The coated surface is illuminated from a short distance with a terahertz light pulse. The reflected signal, containing reflections at the interface of adjacent coating layers, is analysed to determine the thickness of each layer.

The unit has been designed and tested for deployment in manufacturing environments and is available in both manual and automated (robotic) forms.

Being non-contact, it offers significant advantages over existing technologies: for example, line scans and measurement of curved surfaces, including windshield flanges.

The system has been tested by a number of automobile manufacturers. Summary results of trials are discussed.

For more information see http://dsctfocus.org/

Also, see http://www.azom.com/article.aspx?ArticleID=13544

Terahertz Imaging of Three-Dimensional Dehydrated Breast Cancer Tumors

T. Bowman, Y. Wu, J. Gauch, L. K. Campbell, and M. El-Shenawee

Bowman, T., Wu, Y., Gauch, J. et al. J Infrared Milli Terahz Waves (2017) 38: 766. doi:10.1007/s10762-017-0377-y

Abstract

This work presents the application of terahertz imaging to three-dimensional formalin-fixed, paraffin-embedded human breast cancer tumors. The results demonstrate the capability of terahertz for in-depth scanning to produce cross section images without the need to slice the tumor. Samples of tumors excised from women diagnosed with infiltrating ductal carcinoma and lobular carcinoma are investigated using a pulsed terahertz time domain imaging system. A time of flight estimation is used to obtain vertical and horizontal cross section images of tumor tissues embedded in paraffin block. Strong agreement is shown comparing the terahertz images obtained by electronically scanning the tumor in-depth in comparison with histopathology images. The detection of cancer tissue inside the block is found to be accurate to depths over 1 mm. Image processing techniques are applied to provide improved contrast and automation of the obtained terahertz images. In particular, unsharp masking and edge detection methods are found to be most effective for three-dimensional block imaging.

For more information about Professor El-Shenawee see http://terahertz.uark.edu/

For more information about TeraView visit www.teraview.com