MSE Colloquium - Prof. Javiar Tejada
Date: November 01, 2013 from 2:00 pm to 3:00 pm EDT
Location: Room 501, NWC
Contact: For further information regarding this event, please contact Wesley Hattan by sending email to wjh2121@columbia.edu or by calling 2128547860.
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Javier Tejada,
Physics Department, University of Barcelona, Spain

Novel applications of high frequency radiation:


I - THz radiation and Art: a new tool in the inspection of cultural heritage.

II - Potential use of GHz radiation in medicine: study of the ageing of coronary stents.

 
Terahertz (THz) radiation covers the part of electromagnetic spectrum between the microwave and far infrared bands (0.1 to 10 THz). THz waves have been used as a non-destructive evaluation (NDE) tool because they can penetrate many materials -such as plastic, paper, cardboard, canvas, and textiles- and their short wavelength allows to generate images with spatial resolutions in the order of mm to sub-mm.

An interesting use of Thz radiation is the inspection of cultural heritage in applications such as imaging of Egyptian papyrus, spectroscopy of ancient pigments, and imaging and layer analysis of paintings. Recently, Thz radiation has been used to image and analyze the structure of "Sacrifice to Vesta" painted by Spanish artist Francisco de Goya [1]: a feature with a strong resemblance with one of Goya's known signatures is seen in the THz images, which cannot be retrieved either optically or with X-rays. This demonstrates the potential of THz imaging as a complementary technique to X-ray and infrared imaging for the verification and authentication through the detection of features that remain hidden to those techniques.

In this talk I will also show and discuss very recent results on the microwave spectrometry of coronary stents [2]. In these in vitro studies we have proved experimentally that metallic stents of a given nominal size exhibit characteristic resonant frequencies in their microwave scattering spectra. The values of these resonances are very sensitive to the size of the stents and therefore reflect the occurrence of stent structural distortions (fracture and recoil). Moreover, the aforementioned resonances are also sensitive to changes in the dielectric properties of the surrounding medium and may open the door to a preventive diagnosis of restenosis. Current experiments include ex vivo and in vivo trials. Our results can be used to go deeper in the study of microwave spectrometry as a non-invasive and non-ionizing tool to improve the monitoring of patients with metallic stents.

References

[1] C. Seco-Martorell et al. Goya's artwork imaging with Terahertz waves. Optics Express, Vol. 21, Issue 15, pp. 17800-17805 (2013).

[2] G. Arauz-Garofalo et al. Microwave spectrometry for the Evaluation of the Structural Integrity of Metallic Stents.  Submitted to publication