Thermally controllable filter at terahertz region

Shin, Hee Jun, Min-Cheol Lim, Sae-Hyung Kim, Kisang Park, Sung-Wook Choi, and Gyeongsik Ok. "Thermally controllable filter at terahertz region." Infrared Physics & Technology (2017).

Abstract

We experimentally investigated terahertz (THz) filters fabricated using dodecanoic acid (DDA) particles and polyethylene (PE) by performing THz time-domain spectroscopy. Since the refractive indices of DDA and PE are the same in the THz range, no optical scattering occurred when they were mixed. However, heating caused air voids to replace the DDA particles, and the DDA melted into the spaces between the PE particles. Furthermore, as the DDA particle size, heating time, and DDA content increased, the THz band width became narrower. Based on the results, we propose a new, low-cost type of THz filter with a simple manufacturing method.

......................The THz transmission spectra of the DDA were measured from 0.2 THz to 3 THz (6–100 cm−1) using a commercial THz-TDS system (TPS-3000, Teraview, UK) at room temperature and less than 1% humidity........................................

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https://www.sciencedirect.com/science/article/pii/S1350449517306722

A Study of the Effect of a Protein on the Structure of Water in Solution Using Terahertz Time-Domain Spectroscopy

Penkov, Nikita, Valery Yashin, Eugeny Fesenko Jr, Andrew Manokhin, and Eugeny Fesenko. "A Study of the Effect of a Protein on the Structure of Water in Solution Using Terahertz Time-Domain Spectroscopy." Applied Spectroscopy (2017): 0003702817735551.

Abstract

Terahertz time-domain spectroscopy (THz-TDS) was used to determine the spectra (range ¼ 1.2–120 cm-1 ) of aqueous solutions of bovine serum albumin (BSA) at pH range 2.5–10. Under each of the selected pH, BSA molecules exist in a different conformation, compared to other pH values. The spectra were used to calculate the functions of the dielectric permittivity of BSA solutions. Dielectric functions of the aqueous phase of BSA solutions were calculated based on the Bruggeman model, without the contribution of BSA itself. Fitting of the dielectric functions was performed using a model which includes three water spectral bands: two relaxation bands with relaxation times of about 8.28 and 0.3 ps and a vibrational band with a maximum of about 180 cm-1 . The parameters of these bands were determined through fitting and physical interpretation at the molecular level can be provided for each of them. A comparison between the values of model parameters of solutions with BSA and without BSA allowed to conclude that the main effect of BSA is the formation of strongly bound hydration shells in the immediate proximity to the protein molecule. At the same time, the structure of more distant layers of the hydration shells is destroyed, with an increased formation of free water molecules. Some differences are observed in the effect of different BSA conformations on the aqueous phase of solution. The proposed approach can be generalized and applied for studying of a wide class of biological macromolecules in aqueous solutions. 

… by the spectral properties of the solvent water. The fact is that the absorption coefficient of … TPS Spectra 3000 spectrometer (Teraview, UK) in the wave number range from 1.2 to 120 … of electric field into the spectra was performed using the Blackman–Harris 3 apodization function …

for full paper see http://journals.sagepub.com/doi/pdf/10.1177/0003702817735551

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Excitations and relaxation dynamics in multiferroic GeV 4 S 8 studied by terahertz and dielectric spectroscopy

Reschke, S., Zhe Wang, F. Mayr, E. Ruff, P. Lunkenheimer, V. Tsurkan, and A. Loidl. "Excitations and relaxation dynamics in multiferroic GeV 4 S 8 studied by terahertz and dielectric spectroscopy." Physical Review B 96, no. 14 (2017): 144418

Abstract

We report on THz time-domain spectroscopy on multiferroic GeV4S8, which undergoes orbital ordering at a Jahn-Teller transition at 30.5 K and exhibits antiferromagnetic order below 14.6 K. The THz experiments are complemented by dielectric experiments at audio and radio frequencies. We identify a low-lying excitation close to 0.5 THz, which is only weakly temperature dependent and probably corresponds to a molecular excitation within the electronic level scheme of the V4 clusters. In addition, we detect complex temperature-dependent behavior of a low-lying phononic excitation, closely linked to the onset of orbitally driven ferroelectricity. In the high-temperature cubic phase, which is paramagnetic and orbitally disordered, this excitation is of relaxational character becomes an overdamped Lorentzian mode in the orbitally ordered phase below the Jahn-Teller transition, and finally appears as well-defined phonon excitation in the antiferromagnetic state. Abrupt changes in the real and imaginary parts of the complex dielectric permittivity show that orbital ordering appears via a structural phase transition with strong first-order character and that the onset of antiferromagnetic order is accompanied by significant structural changes, which are of first-order character, too. Dielectric spectroscopy documents that at low frequencies, significant dipolar relaxations are present in the orbitally ordered, paramagnetic phase only. In contrast to the closely related GaV4S8, this relaxation dynamics that most likely mirrors coupled orbital and polar fluctuations does not seem to be related to the dynamic processes detected in the THz regime.

… The time-domain THz transmission experiments using a TPS Spectra 3000 spectrometer

for full paper see https://journals.aps.org/prb/abstract/10.1103/PhysRevB.96.144418

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Vibrational states of nano-confined water molecules in beryl investigated by first-principles calculations and optical experiments

Belyanchikov, Mikhail, Elena Zhukova, Sergei Tretiak, Andriy Zhugayevych, Martin Dressel, Frank Uhlig, Jens Smiatek, Maria Fyta, Victor G. Thomas, and Boris Gorshunov. "Vibrational states of nano-confined water molecules in beryl investigated by first principles calculations and optical experiments." Physical Chemistry Chemical Physics (2017).

Abstract

Using quantum mechanical calculations within density functional theory, we provide a comprehensive analysis of infrared-active excitation of water molecules confined in nanocages of a beryl crystal lattice. We calculate infrared-active modes including the translational, librational, and mixed-type resonances of regular and heavy water molecules. The results are compared to the experimental spectra measured for the two principal polarizations of the electric field: parallel and perpendicular to the crystallographic c-axis. Good agreement is achieved between calculated and measured isotopic shifts of the normal modes. We analyze the vibrational modes in connection with the structural characteristics and arrangements of water molecules within the beryl crystal. Specific atomic displacements are assigned to each experimentally detected vibrational mode resolving the properties of nano-confined water on scales not accessible by experiments. Our results elucidate the applicability and efficiency of a combined experimental and computational approach for describing and an in-depth understanding of nano-confined water, and pave the way for future studies of more complex systems.

... dielectric permittivity and optical conductivity were directly determined using quasioptical
spectrometer based on monochromatic and continuously frequency tunable radiation generators –
backward- wave oscillators 33 and a pulsed THz time-domain teraview TPS Spectra ...

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for full paper see http://pubs.rsc.org/en/content/articlelanding/2017/cp/c7cp06472a/unauth#!divAbstract

Global mapping of stratigraphy of an old-master painting using sparsity-based terahertz reflectometry

Dong, Junliang, Alexandre Locquet, Marcello Melis, and D. S. Citrin. "Global mapping of stratigraphy of an old-master painting using sparsity-based terahertz reflectometry." Scientific Reports 7, no. 1 (2017): 15098.

Abstact

The process by which art paintings are produced typically involves the successive applications of preparatory and paint layers to a canvas or other support; however, there is an absence of nondestructive modalities to provide a global mapping of the stratigraphy, information that is crucial for evaluation of its authenticity and attribution, for insights into historical or artist-specific techniques, as well as for conservation. We demonstrate sparsity-based terahertz reflectometry can be applied to extract a detailed 3D mapping of the layer structure of the 17th century easel painting Madonna in Preghiera by the workshop of Giovanni Battista Salvi da Sassoferrato, in which the structure of the canvas support, the ground, imprimatura, underpainting, pictorial, and varnish layers are identified quantitatively. In addition, a hitherto unidentified restoration of the varnish has been found. Our approach unlocks the full promise of terahertz reflectometry to provide a global and detailed account of an easel painting’s stratigraphy by exploiting the sparse deconvolution, without which terahertz reflectometry in the past has only provided a meager tool for the characterization of paintings with paint-layer thicknesses smaller than 50 μm. The proposed modality can also be employed across a broad range of applications in nondestructive testing and biomedical imaging.

.......Methods. THz reflective imaging. A typical THz time-domain system (Teraview TPS Spectra 3000) is employed in this study............ 

for full paper see

https://www.nature.com/articles/s41598-017-15069-2

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Experimental and Theoretical Study of Strong Low-Terahertz Absorption of Thymine

Zhang, W-D., A. Bykhovski, J. A. Deibel, and E. R. Brown. "Experimental and Theoretical Study of Strong Low-Terahertz Absorption of Thymine." Journal of Infrared, Millimeter, and Terahertz Waves 38, no. 12 (2017): 1521-1529.

Abstract

The absorption coefficient of a nucleobase-thymine-in powder form was measured with terahertz spectroscopy in both frequency- and time-domain experiments. For frequencies below 3 THz, a strong signature was observed at 1.27 THz. Furthermore, molecular-dynamic simulations were conducted to reveal that the 1.27 THz absorption signature is related to a transverse optical phonon mode. The simulations also indicated that bound water molecules are vital to the vibrational mode.

... 3 Experimental Methods and Results: Time-Domain Spectroscopy. Next to verify the frequency-domain result, we measured thymine samples with a time-domain system (Teraview TPS Spectra 3000) operating from 0.1 to ∼4.0 THz, and having a dynamic range of ∼60 dB ...

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For full paper see https://link.springer.com/article/10.1007/s10762-017-0420-z

Terahertz non-destructive imaging of cracks and cracking in structures of cement-based materials

Fan, Shujie, Tongchun Li, Jun Zhou, Xiaoqing Liu, Xiaoming Liu, Huijun Qi, and Zhiyong Mu. "Terahertz non-destructive imaging of cracks and cracking in structures of cement-based materials." AIP Advances 7, no. 11 (2017): 115202.

ABSTRACT

Cracks and crack propagation in cement-based materials are key factors leading to failure of structures, affecting safety in construction engineering. This work investigated the application of terahertz (THz) non-destructive imaging to inspections on structures of cement-based materials, so as to explore the potential of THz imaging in crack detection. Two kinds of disk specimens made of plain cement mortar and UHMWPE fiber concrete were prepared respectively. A mechanical expansion load device was deployed to generate cracks and control the whole process of cracking. Experimental tests were carried out on cracked specimens by using a commercial THz time domain spectroscopy (THz-TDS) during loading. The results show that crack opening and propagation could be examined by THz clearly and the material factors influence the ability of crack resistance significantly. It was found that the THz imaging of crack initiation and propagation agrees with the practical phenomenon and supplies more information about damage of samples. It is demonstrated that the damage behavior of structures of cement-based materials can be successfully detected by THz imaging.

....The THz imaging is throughout the whole loading procedure in Section 3.2. All of the TPI experiments were conducted using the TeraView TPS 3000 THz spectrometer,27 the main machine of which is shown in FIG. 5. .....

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For full paper see http://aip.scitation.org/doi/full/10.1063/1.4996053

Nondestructive Imaging of Packaged Microelectronics using Pulsed Terahertz Technology

Tyler Bowman and Magda El-Shenawee (2017) Nondestructive Imaging of Packaged Microelectronics using Pulsed Terahertz Technology. International Symposium on Microelectronics: Fall 2017, Vol. 2017, No. 1, pp. 000709-000714. https://doi.org/10.4071/isom-2017-THP23_160 Abstract This work presents the use of terahertz reflection imaging for nondestructive evaluation of packaged microelectronics. Power MOSFETs and SRAM devices are placed in a pulsed terahertz imaging system in the reflection mode with an incident angle of 30°. From the received signal at each point on the sample under test, the internal structure of the device can be clearly seen. For transistors, terahertz nondestructive imaging has been successful in determining die size and location as well as the bond wire size, number, and connections. High-pass frequency filters are utilized to enhance the image quality for viewing the bond wires. In addition, the terahertz B-scans are used to determine additional information including the vertical position of the bond wires and the die inside the packaged device. For the SRAM, the terahertz nondestructive imaging shows similar effectiveness in defining the layout of the metal connections inside the package and the wire positions. Thus terahertz imaging is shown to have a strong potential for nondestructive evaluation of these devices. ... This work makes use of the TPS Spectra 3000 (Teraview, Ltd., UK) pulsed terahertz imaging and spectroscopy system at the University of Arkansas. The system diagram is shown in Fig. 1a. ... For more information about TeraView visit https://www.azom.com/suppliers.aspx?SupplierID=12145 for full paper see http://www.imapsource.org/doi/abs/10.4071/isom-2017-THP23_160?code=imap-site

Dielectric properties of semi-insulating Fe-doped InP in the terahertz spectral region

Alyabyeva, L. N., E. S. Zhukova, M. A. Belkin, and B. P. Gorshunov. "Dielectric properties of semi-insulating Fe-doped InP in the terahertz spectral region." Scientific Reports 7 (2017).

Abstact

We report the values and the spectral dependence of the real and imaginary parts of the dielectric permittivity of semi-insulating Fe-doped InP crystalline wafers in the 2–700 cm−1 (0.06–21 THz) spectral region at room temperature. The data shows a number of absorption bands that are assigned to one- and two-phonon and impurity-related absorption processes. Unlike the previous studies of undoped or low-doped InP material, our data unveil the dielectric properties of InP that are not screened by strong free-carrier absorption and will be useful for designing a wide variety of InP-based electronic and photonic devices operating in the terahertz spectral range.

......The measurements of the dielectric properties in the ν = 0.21–3.00 THz range (7–100 cm−1) were performed using a pulsed THz TeraView TPS-Spectra-3000 time-domain spectrometer....

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

For full paper see

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5544691/

Preparation, characterization, and spectroscopy study on CdSe quantum dots linked to multi-walled carbon nanotubes

Abouelsayed, A., Badawi Anis, Aly Okasha, Ali M. Ali, W. Elhotaby, and Ahmed SG Khalil. "Preparation, characterization, and spectroscopy study on CdSe quantum dots linked to multi-walled carbon nanotubes." Materials Chemistry and Physics 203 (2018): 1-8.

Abstract

We present spectroscopy study on cadmium selenide (CdSe) quantum dots (QDs) with different particle sizes linked to multi-walled carbon nanotubes (MWCNTs), so-called (CdSe-QDs/MWCNTs), in the ultraviolet and visible frequency range. Drude-Lorentz (DL) model has been used for fitting the absorption spectra for the samples under investigations. Quantitative information about the different excitonic bands and the particle sizes of CdSe-QDs were obtained from the fitting curves and their components. Furthermore, noncontact terahertz time-domain spectroscopy technique was used to compare the optical properties of the MWCNTs and CdSe-QDs/MWCNTs. Using DL model, the optical conductivities have been estimated from the optical parameters obtained from the data extracted from the differential complex terahertz analysis in the frequency range of 0.06–3 THz. The results illustrate that the optical conductivity of MWCNTs is smaller compared to the CdSe-QDs/MWCNTs due to the increased number of free electrons transferred from CdSe QDs and the availability of mobile carriers.

... The absorption bands are deconvoluted and fitted by Lorentzian model. The transmission measurements have been performed in the terahertz frequency range using (TPS spectra 3000 system (Teraview Ltd. England) model under Nitrogen gas N 2 purging. ...

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For full paper see

http://www.sciencedirect.com/science/article/pii/S025405841730754X

Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial

Liu, Mingkai, Mohamad Susli, Dilusha Silva, Gino Putrino, Hemendra Kala, Shuting Fan, Michael Cole et al. "Ultrathin tunable terahertz absorber based on MEMS-driven metamaterial." Microsystems & Nanoengineering 3 (2017): 17033.

Abstact

The realization of high-performance tunable absorbers for terahertz frequencies is crucial for advancing applications such as single-pixel imaging and spectroscopy. Based on the strong position sensitivity of metamaterials’ electromagnetic response, we combine meta-atoms that support strongly localized modes with suspended flat membranes that can be driven electrostatically. This design maximizes the tunability range for small mechanical displacements of the membranes. We employ a micro-electromechanical system technology and successfully fabricate the devices. Our prototype devices are among the best-performing tunable THz absorbers demonstrated to date, with an ultrathin device thickness (~1/50 of the working wavelength), absorption varying between 60% and 80% in the initial state when the membranes remain suspended, and fast switching speed (~27 μs). The absorption is tuned by an applied voltage, with the most marked results achieved when the structure reaches the snap-down state. In this case, the resonance shifts by 4200% of the linewidth (14% of the initial resonance frequency), and the absolute absorption modulation measured at the initial resonance can reach 65%. The demonstrated approach can be further optimized and extended to benefit numerous applications in THz technology.

.....To quantify the absorption properties of the samples, we measured the reflection spectra with a commercial THz time-domain spectrometer (TeraPulse4000, Teraview Ltd, Cambridge, UK). The incident angle of the THz beam in the spectrometer is 30°, and the polarization is dominated by the TE component........

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

For full paper see

https://search.proquest.com/openview/6132b105e4dc0c6b0ea0e3959df2112e/1?pq-origsite=gscholar&cbl=2041946

Qualitative identification of food materials by complex refractive index mapping in the terahertz range

Shin, Hee Jun, Sung-Wook Choi, and Gyeongsik Ok. "Qualitative identification of food materials by complex refractive index mapping in the terahertz range." Food Chemistry (2017).

Abstract

We investigated the feasibility of qualitative food analysis using complex refractive index mapping of food materials in the terahertz (THz) frequency range. We studied optical properties such as the refractive index and absorption coefficient of food materials, including insects as foreign substances, from 0.2–1.3 THz. Although some food materials had a complex composition, their refractive indices were approximated with effective medium values, and therefore, they could be discriminated on the complex refractive index map. To demonstrate food quality inspection with THz imaging, we obtained THz reflective images and time-of-flight imaging of hidden defects in a sugar and milk powder matrix by using time domain THz pulses. Our results indicate that foreign substances can be clearly classified and detected according to the optical parameters of the foods and insects by using THz pulses.

... 2.4. Reflective THz imaging setup. A reflective-mode THz-TDS was used in our experiment. The THz images of samples were obtained by using a two-dimensional scanning module on the THz-TDS (TPS-3000, Teraview, UK) (see Fig. S3(a) of the supplementary material). ...

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

For full paper see

http://www.sciencedirect.com/science/article/pii/S0308814617316874

A non-destructive method for quality control of the pellet distribution within a MUPS tablet by terahertz pulsed imaging

Novikova, Anna, Daniel Markl, J. Axel Zeitler, Thomas Rades, and Claudia S. Leopold. "A non-destructive method for quality control of the pellet distribution within a MUPS tablet by terahertz pulsed imaging." European Journal of Pharmaceutical Sciences (2017).

Abstract

Terahertz pulsed imaging (TPI) was applied to analyse the inner structure of multiple unit pellet system (MUPS) tablets. MUPS tablets containing different amounts of theophylline pellets coated with Eudragit® NE 30 D and with microcrystalline cellulose (MCC) as cushioning agent were analysed. The tablets were imaged by TPI and the results were compared to X-ray microtomography. The terahertz pulse beam propagates through the tablets and is back-reflected at the interface between the MCC matrix and the coated pellets within the tablet causing a peak in the terahertz waveform. Cross-section images of the tablets were extracted at different depths and parallel to the tablet faces from 3D terahertz data to visualize the surface-near structure of the MUPS tablets. The images of the surface-near structure of the MUPS tablets were compared to X-ray microtomography images at the same depths. The surface-near structure could be clearly resolved by TPI at depths between 24 and 152 μm below the tablet surface. An increasing amount of pellets within the MUPS tablets appears to slightly decrease the detectability of the pellets within the tablets by TPI. TPI was shown to be a non-destructive method for the detection of pellets within the tablets and could resolve structures thicker than 30 μm. In conclusion, a proof-of-concept was provided for TPI as a method of quality control for MUPS tablets.

... 2.2.2. Terahertz Pulsed Imaging. Five MUPS tablets, one from each batch, were imaged with a commercial TPI system (TPI™ imaga 2000, TeraView, Cambridge, UK) which represents an automated tablet scanner. As shown in Fig. ...

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

For full paper see 

http://www.sciencedirect.com/science/article/pii/S0928098717305845

Terahertz electrodynamics and superconducting energy gap of NbN

Sim, Kyung Ik, Young Chan Jo, Taewoo Ha, Jong Hyeon Kim, Jae Hoon Kim, and Hirotake Yamamori. "Terahertz electrodynamics and superconducting energy gap of NbN." Journal of the Korean Physical Society 71, no. 9 (2017): 571-574.

We have measured the transmission spectra of the conventional Bardeen-Cooper-Schrieffer (BCS) superconductor niobium nitride (NbN) thin films (Tc = 11 K) using terahertz time-domain spectroscopy (THz-TDS) over the spectral range of 10 - 110 cm −1 and the temperature range of 3.9 - 295 K. We extracted both the real part, σ1, and the imaginary part, σ2, of the optical conductivity, σ̃ = σ1 + iσ2, independently and simultaneously, without a Kramers-Kronig analysis. The superconducting gap Δ(T) was observed in the real part of the conductivity, σ1, below Tc = 11 K with a maximum value of 2Δ(0) = 30 cm −1 and the gap ratio 2Δ(0)/kBTc = 3.92.

... Terahertz transmission spectroscopy was performed with TeraView TPS-3000 Pulse Spectrometer over the frequency range of 2 - 120 cm −1 . The reliable spectral ...

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For full paper see

https://link.springer.com/article/10.3938/jkps.71.571

Biomedical Applications of Terahertz Imaging and Spectroscopy

Feature issue in Biomedical Optics Express

Biomedical Applications of Terahertz Imaging and Spectroscopy

Submission Opens: 1 September 2017

Submission Deadline: 15 November 2017

Biomedical Optics Express will publish a feature issue covering topics in biomedical applications of terahertz imaging and spectroscopy. The scope of the issue encompasses fundamental research, technology development, biomedical studies and clinical applications. The focus will be on:

• THz imaging and spectroscopy of tissues (ex vivo, in vivo, skin, breast, burns)
• Effects of high THz fields on biomedical samples
• Novel THz near-field imaging and spectroscopy
• THz combined with other techniques
• Molecular imaging and therapies
• Microfluidic THz devices
• Ophthalmology
• Gas sensing e.g. exhaled breath analysis
• Protein Spectroscopy
• Pharmaceutical Science e.g. dry dissolution testing

All papers need to present original, previously unpublished work and will be subject to the normal standards and peer-review processes of the journals. Submissions are encouraged from all areas of THz imaging and spectroscopy, but the main novelty is expected to be in biomedical applications. The standard Biomedical Optics Express publication charges will apply to all published articles.

Authors are encouraged to include acceptable supplementary materials (visualizations, tabular data, data sets, design files, or code). Please see OSA's guidelines on supplemental material.

To be eligible for publication, submissions that are based on a conference paper must add substantial and/or significant new information to the original conference summary, in accordance with OSA's Policy on Conference Papers.

Manuscripts must be prepared according to the usual standards for submission to Biomedical Optics Express and must be uploaded through OSA's electronic submission system, specifying from the drop-down menu that the manuscript is for the Feature Issue on Biomedical Applications of Terahertz Imaging and Spectroscopy.

Feature Issue Editors

Vincent Wallace, University of Western Australia, Australia (Lead Editor)
Emma Pickwell-MacPherson, The Chinese University of Hong Kong, China
Zachary Taylor, University of California Los Angeles, USA

Terahertz spectroscopy of charge transport in films of pristine and doped single-wall carbon nanotubes

Gorshunov, B. P., E. S. Zhukova, JuS Starovatykh, M. A. Belyanchikov, A. K. Grebenko, A. V. Bubis, V. I. Tsebro et al. "Terahertz spectroscopy of charge transport in films of pristine and doped single-wall carbon nanotubes." Carbon (2017).

Abstract

Electrical transport mechanisms of 2D carbon nanotube networks are presently under intensive studies. The related experimental data are ambiguous and controversial. We report on terahertz-infrared spectra of optical conductivity and dielectric permittivity of thin transparent films composed of pristine and CuCl- or iodine-doped single-walled carbon nanotubes (SWCNTs) measured in the frequency range from 7 to 25 000 cm−1and at temperatures from 5 to 300 K. Controversially to the existing results, we have not observed a clear signature of the so-called terahertz conductivity peak. Instead, a typical metallic-like frequency- and temperature-dependent behavior of the conductivity and permittivity has been discovered. It was attributed to the high quality interconnected SWCNT network providing the almost free pathways for charge carriers. Applying Drude conductivity model, we have determined the temperature and doping dependences of effective parameters of the carriers in the films: plasma frequency, scattering rate, mobility, mean-free path. The obtained results demonstrate a great potential of the material in the field of electromagnetic applications at frequencies up to few terahertz.

... At terahertz frequencies, from ν ≈ 7 to 60 cm −1 , the spectra of real and imaginary parts of complex conductivity σ*(ν) = σ 1 (ν)+iσ 2 (ν) and dielectric permittivity ε*(ν) = ε′(ν)+iε"(ν) were registered with the TeraView time-domain spectrometer and the quasioptical ...

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

For full paper see

http://www.sciencedirect.com/science/article/pii/S0008622317310722

A split-ring-resonator-based polarization-insensitive ultra broadband filter in terahertz range

Mei Zhu
Proceedings of the Nature Research Society,2017,1,01005
Published Online: 13 October 2017(Article)

Abstract

Split-ring-resonators (SRRs) are one of the most common unit cell designs for metamaterials. Though extensively studied and well understood, such devices are often used as narrow-band filters due to SRRs' sharp resonance to electromagnetic wave. In this work, based on the idea of patterning metal SRRs on both sides of a dielectric substrate while rotating patterns on one side 90o to the other, we show that simple circular SRR can be a building block for broadband filters in terahertz (THz) range. The design principle is detailed with simulation results, showing that such fabricated devices essentially equates to two narrow-band filters on both sides of the substrate connected in series. By changing the unit cell from single SRR to double SRR, we effectively expanded the stop band width of the broadband filter. Devices were created on two types of substrates, 1 mm thick quartz and 100 µm thick polyethylene terephthalate (PET), demonstrating the ease and wide applicability of the fabrication process, while a bandwidth of as large as 1.40 THz has been achieved.

... device are focused simultaneously. The EM responses of the devices were characterized using terahertz time domain spectroscopy (THz-TDS, TeraView TPS 3000) in transmission mode. The measured transmission spectra ...

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

For full paper see

https://nrs.org/journal/pnrs/browse-the-journal/volume-1/a-split-ring-resonator-based-polarization-insensitive-ultra-broadband-filter-in-terahertz-range

TeraView is recruiting

Application sales scientist

TeraView Ltd is the world’s first and leading provider of terahertz solutions to Fortune 500 companies, in a variety of industries. TeraView was created in 2001 from a relationship between the Toshiba Corporation and the Cavendish Laboratory at the University Cambridge. TeraView’s vision is to establish terahertz as the premier imaging and inspection tool for the 21^st century, comparable to the enormous success of X-Ray the latter half of the last century, and more recently ultrasound.

We are currently looking for an Application Sales Scientist based Cambridge, UK.  

The ideal candidate will have;

A good technical background:

• ·         Good first degree in physics or chemistry
• ·         Ph.D. in a physical science 
• ·         A background one or more of the following areas

•   Spectroscopy
•   OTC
•   Ultrasound
•   Multi-spectral imaging
•   Terahertz imaging
•   Terahertz spectroscopy

With desirable skills in:

•     Background in spectroscopy instrumentation
•     MATLAB programming skills

Also, software skills required include in:

·         Office/Word/Excel

Other skills, experience and characteristics required:

·         Technical background

·         Collaborative team player

·         Proactive mind-set

·         Highly organised

·         Attention to detail

·         Being able to work with minimal supervision

·         A valid driving licence is required

The key tasks they will engage in:

• ·    Providing technical advice to customers at both pre- and post-sales stages
• ·    Providing support and explanation to customers by email, by phone  and in person
• ·    Develop technical proposals, quotations, and orders
• ·    Generate and approve pricing, schedule and product offering for  quotation to prospective  customers
•        Plan and direct marketing activity such as marketing strategy  development, marketing      materials generation, tradeshow support  and lead generation activities
•        Attending conference and technical meetings
• ·    Supporting the customer by addressing their requirements in a wide  variety of application areas
• ·    Maintain technical service database and reference files, documenting  response times and delivering on commitments made to customer
• ·    Communicate customer and product feedback to Marketing and R&D  to further improve quality and the customer experience
• ·    Contribute to technical publications, application notes and SOPs.
• ·    First point of contact for customer feedback
• ·    The candidate will be expected to travel up 50% of their time world-wide.

To apply for this vacancy, please send your CV and a support letter in their application detailing why they are right for the job.  These should be sent to:-recruitment@teraview.com.

TeraView offers flexible working hours with an excellent salary and benefits package, along with the opportunity for highly-motivated staff to work together in a friendly, intellectually stimulating and challenging environment.

We are an equal opportunities employer and pride ourselves on our diverse workforce.  For further information and background on the company, please visit our website on: www.teraview.com.

No agencies please.