Wednesday, 22 June 2016

Effect of swelling of a photoresist on electromagnetic resonance of terahertz metamaterials

Wei-Fan Chiang ; Yu-Ting Hsieh ; Song-Hang Wang ; Hsin-Yuan Miao ; Jih-Hsin Liu ; and Chia-Yi Huang


This work uses isopropyl alcohol (IPA) to develop a photoresist. IPA dissolves the photoresist that is not exposed to UV light, and swells the photoresist that is exposed to UV light. The swelling of the photoresist distorts the split-ring resonators (SRRs). The distorted SRRs have a larger loop length, smaller line width, and smaller split gap than undistorted SRRs. The change in the dimensions of the SRRs is caused by the extension of the SRR arms in their longitudinal directions. The resonance frequency of the distorted SRRs is smaller than that of the undistorted SRRs, and the resonance frequency decreases with the development time.

The resonance frequency of the distorted SRRs depends on not only their dimensions, but also the bending of their arms. The distorted SRRs in this work have a frequency tuning range with a maximum width of 0.13 THz. The method that is proposed herein uses IPA to fabricate passively tunable terahertz metamaterials, which exhibit the advantages of high reliability, low cost, and ease of fabrication.

Full article available here.

Bow-Tie Plasmonic Arrays Loaded with Graphene for the Fast Room Temperature Detection of Terahertz Quantum Cascade Lasers

Riccardo Degl'Innocenti ; Long Xiao ; David Jessop ; Stephen Kindness ; Christian W. Sol ; Yuan Ren ; Hungyen Lin ; Axel J. Zeitler ; Philipp Braeuninger-Weimer ; Stephan Hofmann ; Harvey Beere ; David Ritchie


We present a fast room temperature terahertz detector based on interdigitated bow-tie antennas asymmetrically doping and contacting graphene. The device was tested with a 2 THz quantum cascade laser yielding a responsivity of 0.5 ╬╝AW-1.

Full article available here.

Studying the Kinetics of n-Butyl-Cyanoacrylate Tissue Adhesive and Its Oily Mixtures

Marie Nedvedova ; Vojtech Kresalek, ; Hana Vaskova ; Ivo Provaznik


This study deals with the measurement of the kinetics of tissue adhesives used for supporting the hemostasis and wound closure during surgical intervention. There are available several types of adhesives of different composition which is closely related with their application. When selecting an appropriate adhesive, the time of curing could play an important role because some applications may require very fast polymerization for prompt vessel or wound closure; conversely, some situations need slower solidification because of longer manipulation with the glue during surgery.

The terahertz time-domain spectroscopy is used for studying the kinetics of the n-butyl-cyanoacrylate glue in this study. An oily substance is added to the glue samples to slow the reaction rate. The technique of attenuated total reflection is used in this application; the defined amount of glue sample or its mixture is applied on the silicon crystal and the terahertz response is measured in time. This time dependences are analyzed to find time constants for mathematical description of the glue kinetics. Further, the investigated samples were analyzed using light microscopy and Raman spectroscopy for description of the structures and compositions.

Full article here.

Tuesday, 7 June 2016

Transmission and Reflection Terahertz Spectroscopy of Insensitive Melt-Cast High-Explosive Materials

Norbert Palka, Mateusz Szala


Currently, artillery shells and grenades that are introduced into the market are based on melt-castable insensitive high explosives (IHEs), which do not explode while they run a risk of impact, heat or shrapnel. Particles of explosives (such as hexogen, nitroguanidine and nitrotriazolone) are suspended in different proportions in a matrix of 2.4-dinitroanisole.

In this paper, we investigated samples of commonly used IHEs: PAX-41, IMX-104 and IMX-101, whose internal structures were determined by a scanning electron microscope. Terahertz time domain spectroscopy was applied in both transmission and reflection configurations. At first, the complex refraction indices of four pure constituents creating IHEs were determined and became the basis of further calculations.

Next, the experimentally determined transmission and reflection spectra of IHEs and pure constituents were compared with theoretical considerations. The influence of the grain size of constituent material and scattering on the reflection spectra was analysed, and good agreement between the experimental and theoretical data was achieved.

Full article available here.

Friday, 3 June 2016

CLEO 2016: Terahertz Science and Technologies

TeraView's Dr Philip Taday will preside over the Terahertz Measurement Systems and Applications session at this years CLEO 2016.

The session will take place on Monday June 6th, between 8am - 10am (Meeting Room 212 B, Convention Center)

CLEO 2016 runs from the 5th to the 10th of June.

Full details of the event can be found here.