Tuesday, 21 April 2015

Don’t Miss the Impressive Line-up at the CLEO Plenary Session

CLEO:2015 | Technical Conference:
10-15 May 2015 | Short Courses: 10-12 May 2015 | Exposition: 12-14 May 2015 | San Jose, CA

Monday Plenary Session

Eric Betzig, Howard Hughes Medical Institute, USA
Nobel Prize Winner in Chemistry 2014
Imaging Life at High Spatiotemporal Resolution

Tony Heinz, Columbia University, USA
Electrons in Atomically Thin Two-dimensional Crystals

Stephan W. Hell, Max Planck Institute for Biophysical Chemistry, Germany
Nobel Prize Winner in Chemistry 2014
Nanoscopy with Focused Light

W. E. Moerner, Stanford University, USA
Nobel Prize Winner in Chemistry 2014
Foundations of Super-Resolution Microscopy

Tuesday Plenary Session

Hiroshi Amano, Nagoya University, Japan
Nobel Prize Winner in Physics 2014
Current and Future of Solid State Lighting

Steven Chu, Stanford University, USA
Nobel Prize Winner in Physics 1997
Microscopy 2.0

Wednesday International Year of Light Plenary Session

Shuji Nakamura, University of California Santa Barbara, USA
Nobel Prize Winner in Physics 2014
Energy Savings by LED Lighting

Miles Padgett, University of Glasgow Scotland, UK
Light’s Twist

Friday, 17 April 2015

Continuously tunable and fast-response terahertz metamaterials using in-plane switching dual-frequency liquid crystal cells

Chia-Yi Huang, Chia-Chun Chen, Wei-Fan Chiang, Min-Cheng Tsai, Shun-An Jiang, Tsung-Hao Chang, and Song-Hang Wang


A metamaterial that is embedded into an in-plane switching dual-frequency liquid crystal cell is used to develop an electrically controllable terahertz metamaterial. The resonance peak of the metamaterial can be redshifted and blueshifted as the frequency of an external voltage is switched, and the response times for the redshift and blueshift are 1.044 ms and 1.376 ms, respectively. A simulation confirms the spectral redshift and blueshift. The variation in the peak frequency as a function of applied frequency at the external voltage is presented. Experimental results show that the resonance peak of the metamaterial can be continuously tuned within a frequency range of 15 GHz as the applied frequency is switched between 19 kHz and 22 kHz. Therefore, this metamaterial is a continuously tunable and fast-response terahertz filter and could be used for terahertz imaging and terahertz telecommunications.

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

Thursday, 16 April 2015

Comparison of damage behaviour of different plant fibre composites under laser impact loading

F. Touchard, L. Berthe, P. Malinowski, S. Opoka, M. Boustie, L. Chocinski-Arnault and W. Ostachowicz


The high strain rate behaviour of the eco-composites, when submitted to laser impact loading, is not well known yet. Crucial questions are still open: influence of plant fiber length and distribution on the composite impact behaviour, types of damage induced by impact loading, the way the failure occurs, etc. We present the very first results of a collaborative research involving the institutions PPRIME- Poitiers and PIMM-Paris, and IMP PAN-Gdansk-Poland. A comparison of laser shock induced damage is realised, based on observations of sample back faces for several types of eco-composites. Spallation, residual blister and inside delamination, depending on the fibre length in tested composites have been observed. The ability of the Terahertz technique for internal damage detection is demonstrated.

Wednesday, 15 April 2015

New trends in non-destructive assessment of aerospace structures

Wieslaw M. Ostachowicz ; Pawel H. Malinowski ; Tomasz Wandowski


The scope of the paper includes non–destructive assessment of the structure's material condition, for the aerospace structures during its useful lifetime. The paper presents multidisciplinary technologies devoted to development and implementation of methods and systems that realize inspection and damage detection by non–destructive methods. The paper covers several disciplines which are based on topics such as piezoelectric transducers, elastic waves propagation phenomenon, structural vibrations analysis, electro–mechanical impedance method, terahertz technique, laser induced fluorescence and 3D laser vibrometry applications. Among various techniques available the paper presents selected numerical simulations and experimental validations of considered structures. Authors address also the problem of adhesive bonding in the case of carbon fiber reinforced polymers (CFRP). Techniques for detection of weak bonds are presented together with signal processing approaches. The reported investigations concern weak adhesive bonds caused by both manufacturing (e.g. release agent, poor curing) and in–service contaminations (e.g. moisture). Also the paper provides helpful information about dispersion, mode conversion and wave scattering from stiffeners and boundaries. It addresses the problem of optimisation of excitation signal parameters and sensor placement, as well as analysis of signals reflected from damage. It also includes a variety of techniques being related to diagnostics (damage size estimation and damage type recognition) and prognostics. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Tuesday, 14 April 2015

Terahertz single conductance quantum and topological phase transitions in topological insulator Bi2Se3 ultrathin films

Byung Cheol Park, Tae-Hyeon Kim, Kyung Ik Sim, Boyoun Kang, Jeong Won Kim, Beongki Cho, Kwang-Ho Jeong, Mann-Ho Cho & Jae Hoon Kim


Strong spin-orbit interaction and time-reversal symmetry in topological insulators generate novel quantum states called topological surface states. Their study provides unique opportunities to explore exotic phenomena such as spin Hall effects and topological phase transitions, relevant to the development of quantum devices for spintronics and quantum computation. Although ultrahigh-vacuum surface probes can identify individual topological surface states, standard electrical and optical experiments have so far been hampered by the interference of bulk and quantum well states. Here, with terahertz time-domain spectroscopy of ultrathin Bi2Se3 films, we give evidence for topological phase transitions, a single conductance quantum per topological surface state, and a quantized terahertz absorbance of 2.9% (four times the fine structure constant). Our experiment demonstrates the feasibility to isolate, detect and manipulate topological surface states in the ambient at room temperature for future fundamental research on the novel physics of topological insulators and their practical applications.

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

Friday, 10 April 2015

Quantification of residual crystallinity of ball-milled, commercially available, anhydrous β-lactose by differential scanning calorimetry and terahertz spectroscopy

Geoff Smith, Amjad Hussain, Nadeem Irfan Bukhari, Irina Ermolina


The quantification of crystallinity is necessary in order to be able to control the milling process. In this study, the changes in the amount of residual crystallinity of ball-milled anhydrous β-lactose (β-LA), for periods up to 60 min, were evaluated by differential scanning calorimetry (DSC) and by terahertz pulsed spectroscopy. The percentage of residual crystallinity using DSC was estimated by two methods: The first method was based on the measurement of the melting of the crystalline part, while the second was based on the measurement of the devitrification of the amorphous part. Peaks in THz spectra, related to the residual crystalline material were analyzed by two methods: (1) area under peak and (2) partial least square. The milled samples of β-LA show a monotonic decrease in crystallinity with milling time, although the quantitative analysis performed by different techniques reveals very different results. THz technique gives significantly lower estimates for % crystallinity (in the early time period) than that calculated from the DSC data, possibly because of the recrystallization of amorphous form during sample preparation. The comparison of residual crystallinity of β-LA with its hydrated counterpart [i.e., α-lactose monohydrate (α-LMH)] has shown that the amount of amorphous material produced from the α-LMH is 20–30 % greater than from β-LA at extended milling times (i.e. 60 min).

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

Thursday, 9 April 2015

Comparisons of intra-tablet coating variability using DEM simulations, asymptotic limit models, and experiments

Ben Freireich, Rahul Kumar, William Ketterhagen, Ke Su, Carl Wassgren, J. Axel Zeitler


Discrete element method (DEM) computer simulations are used to investigate intra-tablet coating thickness variability. Two new post-processing algorithms are presented. The first algorithm uses an image-based method to track the exposure to a simulated spray of small area panels on each tablet's surface so that the distribution of spray exposure times over the tablet's surface can be determined directly from DEM data. The second algorithm predicts the asymptotic limit of intra-tablet coating uniformity. This second algorithm includes the influence of tablet orientation and shadowing when considering exposure to the spray, averaged over many tablets.

The DEM simulations produce the first direct evidence that non-spherical tablets approach asymptotic intra-tablet coating variability values. The asymptotic limits are predicted well using the new asymptotic prediction model. In general, tablet caps have thicker coatings than tablet bands. Moreover, tablets that have a more elongated shape tend to have less coating on the smaller radius of curvature portions of the bands. Of particular importance in this new asymptotic modeling approach is the inclusion of shadowing effects. When shadowing is not included and only tablet orientation is considered, the predictions over-predict the asymptotic intra-tablet coating variability values and also change the observed rank order of the asymptotic values for different tablet shapes. The asymptotic intra-tablet coating variability values using the new algorithm correlate reasonably well with tablet sphericity, with increasing sphericity improving coating uniformity.

This paper also presents the first attempt to directly compare experimental and simulated coating thickness distributions. The asymptotic coating thickness predictions compare well qualitatively with terahertz thickness measurements made on tablets from coating experiments. Unfortunately, only qualitative comparisons could be made due to the limited number of tablets sampled experimentally and differences in spray zone areas and flux distributions. The tablets in the experiments, however, displayed similar features as those found in the simulations.

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

Wednesday, 8 April 2015

TeraPulse 4000 – TeraView ships and delivers its first unit

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.

For the full article and more information on TeraView and the TeraPulse 4000 be sure to visit:

Thursday, 2 April 2015

Temperature evolution of dielectric response spectra of stillwellite-like glasses in the terahertz and infrared ranges

G. A. Komandin, O. E. Porodinkov, Yu. G. Goncharov, I. E. Spektor, L. D. Iskhakova, V. N. Sigaev, S. V. Lotarev, V. I. Torgashev


The reflectance and transmittance spectra of the PrBGeO5 glass were measured in the terahertz and infrared ranges. At low temperatures, an increase in the permittivity and the appearance of narrow resonance-type lines in the terahertz range were revealed. The complex permittivity spectra were calculated from the Fresnel and Kramers-Kronig formulas.

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

Wednesday, 1 April 2015

Facile metal transfer method for fabricating unconventional metamaterial devices

Mei Zhu and Chengkuo Lee


We report a facile metal transfer method to create metal patterns on polydimethylsiloxane (PDMS) surface. The metals were first patterned on polyethylene terephthalate (PET) substrate, and then transferred to PDMS simply by oxygen plasma treatment. The transfer was enabled by weakened metal-PET adhesion due to undercut and charge repulsion. In this way, we got rid of adhesion layers and sacrificial layers that were required by conventional methods. Ours is a fast and convenient method as it takes place at room temperature with just a gentle contact of PET and PDMS. The resolution of this method was found to be in sub-micron range and the morphologies of different transferred patterns were characterized. With such a method, we successfully fabricated some unconventional metamaterial devices, including a double-sided broadband THz filter with a stop band bandwidth of 1.4 THz, and devices on paper, fabric, leaf and nonplanar surfaces.