Wavelet denoising and reconstruction of a microneedle embedded in human skin ex-vivo using terahertz pulsed reflectance

Mueller-Holtz, Martin ; Smith, Geoff

Abstract

Biological tissue can show promising features in the terahertz region of the electro-magnetic spectrum but face the problem that the signal to noise ratio can be poor due to the low energy output from the measurement instrument coupled with the high absorbance of water in biological tissue. Wavelet denoising and reconstruction are known to be suitable digital signal processing filters for reflected terahertz energy when appropriate thresholds, scales and mother-wavelets are chosen. In this article, we therefore describe a Wavelet transform-based method for denoising reflections of THz energy from ex-vivo human skin with an embedded microneedle. The wavelet reconstruction was then successfully used to identify the microneedle from the reflected waveform. This technique is potentially useful to enhance in-depth analysis and visualisation of underlying skin layers, lesions and penetration depth for targeted drug delivery.

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

Full Article: http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6945175&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D6945175

Applications of terahertz pulsed technology in non destructive testing

TeraView would like to remind you that TeraView's Dr. Philip Taday will be presenting on the 26th of November.

Technisches Kolloquium - Terahertz technology for NDT will be held on the 26th of November 2014 in the conference/class room in Zorneding, Munich.

This event will be open to all our customers and to contacts of our partner Allianz.'

The event is free of charge and will be attended by Dr. Philip Taday who will be presenting a talk on: “Applications of terahertz pulsed technology in non-destructive testing”

Link to event details - (PDF in German): 

http://www.gwp.eu/fileadmin/img/academy_Dateien/1314_TKQ_Applications_of_THz_Rev2.pdf

Assignment of the Terahertz Spectra of Crystalline Copper Sulfate and Its Hydrates via Solid-State Density Functional Theory

Michael Thomas Ruggiero , Tiphaine Bardon , Matija Strlic , Phil F. Taday , and Timothy Michael Korter

Abstract

Terahertz (THz) vibrational spectroscopy is a promising tool for the non-destructive and potentially non-invasive characterization of historical objects, which can provide information on the materials used for their production as well as identify and monitor their chemical degradation. Copper sulfate (CuSO4) has drawn interest due to its inclusion in the preparation of iron gall inks found in historical artwork and documents. Copper sulfate rapidly forms hydrates which contribute to the formulation of these ink species, and may influence their corrosive nature. In this study, copper sulfate has been studied using a combination of THz time-domain spectroscopy, powder X-ray diffraction (PXRD), and solid-state density functional theory (DFT) in order to better understand the spectral absorbances in the THz region. The results have revealed that the THz spectrum of commercially available “anhydrous” copper sulfate results from the presence of not only the anhydrous form, but also the monohydrate (CuSO4⋅H2O) and trihydrate (CuSO4⋅3H2O) forms. Complete assignment of the experimental spectrum was achieved through a comparison of density functionals and extensive investigation of the influence of basis set polarization functions on the bonding interactions, lattice parameters, and low-frequency motions in these crystalline solids.

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

Full Article: http://pubs.acs.org/doi/abs/10.1021/jp507927c

Polarization-insensitive metamaterial absorber of selective response in terahertz frequency range

B Grześkiewicz, A Sierakowski, J Marczewski, N Pałka and E Wolarz

Abstract

We present an experimental and numerical analysis of a planar metamaterial that selectively absorbs terahertz radiation. The metamaterial is produced as a planar two-dimensional network of electromagnetic resonators and is characterized by electric and magnetic responses in a narrow frequency range. The unit cell of the metamaterial has fourfold symmetry about the axis perpendicular to the planes containing the metallic resonators. Such a planar metamaterial is polarization-insensitive to the electromagnetic waves. A good agreement of the absorption characteristics obtained from the numerical simulations and from the spectroscopic experiments is shown. The analysis of wave impedance, refractive index, permittivity and permeability of the metamaterial allows the identification of the characteristic electromagnetic resonance and antiresonance in the system. It is shown that the absorption is mostly the result of the electric field energy accumulation in the metamaterial absorber.

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

Full Article: http://iopscience.iop.org/2040-8986/16/10/105104

THz Metal Mesh Filters On Electrically Thick Fused Silica Substrates

William Otter, Fangjing Hu, Stepan Lucyszyn, Jonathan Hazell,

Abstract

This paper shows simulated and measured results of ultra-low cost metal mesh filters on electrically thick substrates for millimeter-wave and THz bands. It provides a broad overview of metal mesh filters currently available and suggest why it is worth moving to an electrically thick substrate for ultra-low cost applications. We demonstrate scalable traditional metal mesh filters on 525 µm thick fused silica substrates. In addition, trapped-mode excitation is exploited to improve out-of-band rejection at higher frequencies. The measured results prove that these filters are scalable in the THz range using cost-effective micromachining manufacturing. This work opens up the possibility of using electrically thick metal mesh filters for ultra-low cost applications. 

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

Full Article: http://www.irmmw-thz2014.org/sites/default/files/W2_A-19.10_Otter.pdf