Flexible terahertz and FarIR polymer‐supported filter

Sanphuang, Varittha, and Niru K. Nahar. "Flexible terahertz and FarIR polymer‐supported filter." Microwave and Optical Technology Letters.

Abstract

We present the design, fabrication, and measurement of a terahertz (THz) polymer‐supported filter. A periodic structure, frequency selective surfaces (FSS) is employed to provide bandpass characteristic for this filter design with polyimide (PI) film as a substrate. This PI film (13 μm thick) is very thin and thus provides a flexible support to the filter. The average extracted dielectric constant ε r is 3.35 and the average refractive index n s is 1.84. The final filter structure was fabricated using standard microfabrication process. The measured transmission response shows high percentage of transmission (~80%) with the peak at 0.58 THz and sharp roll‐off that covers the broad range of frequency from 0.1 to 1 THz (wavelength of 300 μm‐3000 μm).

For full paper see https://onlinelibrary.wiley.com/doi/abs/10.1002/mop.31414

For more information about TeraView visit www.teraview.com 

Hydration of gelatin molecules studied with terahertz time-domain spectroscopy

Fan, S., Z. Qian, and V. P. Wallace. "Hydration of gelatin molecules studied with terahertz time-domain spectroscopy." In Infrared, Millimeter-Wave, and Terahertz Technologies V, vol. 10826, p. 1082604. International Society for Optics and Photonics, 2018.

Abstract

Gelatin is an irreversible hydrolyzed form of collagen having similar amino acid compositeswith its parent collagen. The hydrogen atoms on the side chains of the long peptide strings can weakly bond with their surrounding gelatin as well as water molecules in aqueous environment, forming a cross-linked 3D matrix. Gelatin has been used as a model for soft tissue phantoms in several medical imaging studies including in terahertz imaging. In the terahertz regime, the dielectric property of the gelatin relies largely on its hydration status and the relationship has been shown to be non-linear. It is therefore essential to study the change of the dielectric properties with respect to the hydration status so as to accurately mimic the properties of fresh biological tissues in the terahertz spectrum. .....

for full paper see https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10826/1082604/Hydration-of-gelatin-molecules-studied-with-terahertz-time-domain-spectroscopy/10.1117/12.2502287.short?SSO=1

… The heated gelatin solutions were poured into a liquid holder with a window made of
z-cut quartz as the bottom material. The sample holder was set on the reflection imaging stage of the TeraPulse 4000 system (TeraView Ltd, Cambridge, UK) …

For more information about TeraView visit https://teraview.com/terapulse/

Application of THz spectroscopy for localisation of fibre optics embedded into glass fibre reinforced composite

Mieloszyk, Magdalena, Katarzyna Majewska, and Wieslaw Ostachowicz. "Application of THz spectroscopy for localisation of fibre optics embedded into glass fibre reinforced composite." Composite Structures (2018).

Abstract

Recently, in many industrial branches (e.g. aviation, marine or civil engineering) metal elements are replacing by composite ones. To ensure their reliability structural health monitoring systems also based on fibre optics sensors (embedded into or mounted on composite structure) are widely applied.

In the paper THz spectroscopy technique was proposed for detection and localisation of glass fibre optics embedded into a glass fibre reinforced polymer. The analysis was performed on a four-layer sample manufactured by infusion method. During this investigation both the sample surfaces roughness as well as fibre optics arrangements (according to the THz spectrometer axes) were examined. For this purpose THz images of internal structure of the sample were presented. Additionally two methods (in time and frequency domains) for quick determining of fibre optics location are presented. The first one is based on local changes in signal amplitudes while the second – on differences in power spectrum.

for full paper see https://www.sciencedirect.com/science/article/pii/S0263822318315423

… 2.1. THz unit. During the experimental investigation the THz spectrometer (TPS Spectra 3000 THz Pulsed Imaging and Spectroscopy from TeraView ® ), presented in Fig. 2, was used. The system contains two main parts: a measurement chamber and a scanning unit …

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Polarizability of Aspirin at Terahertz Frequencies Using Terahertz Time Domain Spectroscopy (THz-TDS)

Zhang, Tianyao, Zhaohi Zhang, and Mark Arnold. "EXPRESS: Polarizability of Aspirin at Terahertz Frequencies Using Terahertz Time Domain Spectroscopy (THz-TDS)." Applied Spectroscopy (2018): 0003702818815177.

A novel application of terahertz time-domain spectroscopy (THz-TDS) is described for the determination of permittivity and polarizability of organic crystals, as exemplified by measurements with the polymorph I form of crystalline aspirin (acetylsalicylic acid). The coherent nature of the THz pulse experiment, coupled with gated-detection, permits direct measure of differences in the phase angle of the electric field vector after passing through a pellet composed of the aspirin crystals embedded within an inert polymer matrix. An effective …

For full paper see https://journals.sagepub.com/doi/10.1177/0003702818815177

… Relevant crystal structure information for this aspirin polymorph is listed in Table II. The

THz spectra were collected by using a TeraView TPS Spectra 1000D THz time- domain spectrometer (TeraView Limited, Cambridge, UK). Details of the instrument can be..

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