This paper examines the scattering effect of knit lines and voids in SOFI through simulations of THz interrogation at non-normal angles of incidence using focused single-cycle plane waves. We have developed a framework which accounts for the presence of knit lines in modeling the electromagnetic propagation of interrogating pulses in SOFI. We were able to compute, using results from a laboratory experiment, estimates for the index of refraction in both the knit lines and the surrounding low-density foam based on measured values from time-of-flight experiments and observable material properties. Our efforts here provide an approach to enhance the accuracy of a model by making it more representative of the material in question and the signal used to interrogate that material. The results themselves suggest that accurate modeling of the angle of incidence is important to quantify the amplitude of the reflected signal, while modeling the focusing captures the clear distinction between the reflections from the front versus the back of the void. Sufficient experimental results for comparison are difficult to obtain since the amplitude of reflections off of low density materials is very low to immeasurable using currently available power sources at the THz frequency. Therefore, the results of this paper should be considered as motivation for the development of high power THz devices. For now, experimental information is collected from the aluminum reflection. More work needs to be done to match simulations to this data, including adding attenuation, possibly via coupling Maxwell's equations to a time domain model of a scattering mechanism.


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    Title :

    2D Modeling of pulsed THz interrogation of SOFI with knit lines


    Additional title:

    Zweidimensionale Modellierung von Terahertz-Impuls-Untersuchung von SOFI mit Faserlinien


    Contributors:
    Banks, H.T. (author) / Gibson, N.L. (author) / Winfree, W.P. (author)


    Publication date :

    2007


    Size :

    7 Seiten, 5 Bilder, 7 Quellen





    Type of media :

    Conference paper


    Type of material :

    Storage medium


    Language :

    English




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