Churchley D.,Glaxosmithkline |
Lynch R.J.M.,Glaxosmithkline |
Lippert F.,Indiana University |
Eder J.S.O.,Indiana University |
And 2 more authors.
Journal of Biomedical Optics | Year: 2011
We compare terahertz-pulsed imaging (TPI) with transverse microradiography (TMR) and microinden-tation to measure remineralization of artificial caries lesions. Lesions are formed in bovine enamel using a solution of 0.1 M lactic acid/0.2% Carbopol C907 and 50% saturated with hydroxyapatite adjusted to pH 5.0. The 20-day experimental protocol consists of four 1 min treatment periods with dentifrices containing 10, 675, 1385, and 2700 ppm fluoride, a 4-h/day acid challenge, and, for the remaining time, specimens are stored in a 50:50 pooled human/artificial saliva mixture. Each specimen is imaged at the focal point of the terahertz beam (data-point spacing = 50 μm). The time-domain data are used to calculate the refractive index volume percent profile throughout the lesion, and the differences in the integrated areas between the baseline and post-treatment profiles are used to calculate ΔΔZ (THz). In addition, the change from baseline in both the lesion depth and the intensity of the reflected pulse from the air/enamel interface is determined. Statistically significant Pearson correlation coefficients are observed between TPI and TMR/microindentation (P < 0.05). We demonstrate that TPI has potential as a research tool for hard tissue imaging. © 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). Source
Rihani S.,University of Cambridge |
Page H.,TeraView |
Beere H.E.,University of Cambridge
Superlattices and Microstructures | Year: 2010
We present a study on quasibound states in multiple quantum well structures using a finite element model (FEM). The FEM is implemented for solving the effective mass Schrödinger equation in arbitrary layered semiconductor nanostructures with an arbitrary applied potential. The model also includes nonparabolicity effects by using an energy dependent effective mass, where the resulting nonlinear eigenvalue problem was solved using an iterative approach. We focus on quasibound/continuum states above the barrier potential and show that such states can be determined using cyclic boundary conditions. This new method enables the determination of both bound and quasibound states simultaneously, making it more efficient than other methods where different boundary conditions have to be used in extracting the relevant states. Furthermore, the new method lifted the problem of quasibound state divergence commonly seen with many other methods of calculation. Hence enabling accurate determination of dipole matrix elements involving both bound and quasibound states. Such calculations are vital in the design of intersubband optoelectronic devices and reveal the interesting properties of quasibound states above the potential barriers. © 2009 Elsevier Ltd. All rights reserved. Source
Agency: GTR | Branch: Innovate UK | Program: | Phase: Collaborative Research & Development | Award Amount: 522.04K | Year: 2008
Agency: GTR | Branch: Innovate UK | Program: | Phase: Collaborative Research & Development | Award Amount: 218.99K | Year: 2013
New paint production processes in the automative industry have the potential to be much more cost and materials efficient but require higher levels of process monitoring than are currently available. With its terahertz technology, TeraView Ltd has demonstrated the offline ability to rapidly measure simultaneously several coating layers in a non-contact manner. In this project, we will develop a technology demonstrator to monitor coating thickness in real time on the production line. Several car manufacturers including Ford UK, a consortium member, have expressed interest in applying this technology to assist in monitoring and control of the painting process. The project represents an initial £70M+ business opportunity and, in terahertz, introduces a new sensor technology to the automotive industry. Technical innovations include real time signal processing, roboting control of the terahertz sensor and creation of a ruggedised sensor suitable for industrial deployment.
Agency: GTR | Branch: Innovate UK | Program: | Phase: Smart - Development of Prototype | Award Amount: 250.00K | Year: 2012
TeraView has developed a state-of-the-art system (Fig A2) for fault location in semiconductor packages, based on its proprietary terahertz pulse generation and detection technology. This system is used for failure analysis (FA) on semiconductor packages. Pins, balls or pads are selected for probing using a manual micropositioning system. Measurements can typically be made every few minutes, including the time required for ball/pin selection and contacting. The system works by sending a terahertz pulse into the total package along the interconnects. The magnitude and phase of subsequent reflections reveal the presence and location of open circuits, short circuits and resistive contacts. Customers include Intel and Samsung. This project will develop a prototype test equipment for fast and automated inspection of advanced Integrated Circuit (IC) packages used in mobile computing devices such as smart phones and tablet computing devices. It is estimated that 74% of 2012 semiconductor growth will be in such devices. Device miniaturisation demands much improved resolution in fault detection which current techniques are unable to offer. Further, it requires many silicon dies to be connected together in a package. The lack of reliability of the connections between two dies is an additional failure mechanism, the location of which cannot be easily determined by existing technology. This is a major problem but is one which our technology is uniquely able to solve.