Terahertz transmission through freshly excised biological tissue is limited by the tissue's high water content.
Tissue fixation methods that remove water, such as fixation in Formalin, destroy the structural information
of proteins hence are not suitable for THz applications. Dehydration is one possible method for revealing the
tissue's underlying molecular structure and components. In this study, we measured the THz responses over time
of dehydrating fresh, necrotic and lyophilized rat tissue. Our results show that as expected, THz absorption
increases dramatically with drying and tissue freshness can be maintained through lyophilization. Dehydrated
biological tissue with retained molecular structure can be useful for future laser-based THz wave molecular
The reflection characteristic of terahertz radiation (T-rays) in stratified media is being explored through the use of computer models. When T-rays are reflected off a sample, the measured T-ray signal contains coherent spectroscopic information about the sample. In the time domain, this spectroscopic information becomes the time response of the sample-a useful method for determining layer thickness and the number of interfaces in the sample. In order to confidently determine thickness and interfaces, the propagation characteristic of T-rays in a stratified medium needs to be understood. Internal reflections, interference, and water absorption within the layers can significantly alter the T-ray signal. This paper reports on a study of T-ray propagation in tissue layers inside the head, in reflection mode. Simulated results are presented and discussed.
Terahertz imaging is presently in its exploratory stage. Although plots of time versus terahertz amplitude, and frequency versus terahertz magnitude are some of the most common ways of analyzing terahertz data, no standard rendering technique has been established. While existing methods are indispensable, improvements to how terahertz data is rendered and analyzed should be explored so that new techniques can complement existing ones and/or provide a means of displaying new information that existing methods cannot. This paper reports on one solution to terahertz imaging: an implementation of a new form of phase contrast imaging, which is based on a well-established technique for optical microscopy. This will provide us with a further way of interpreting information from terahertz imaging systems.