Terahertz sources and detectors and their application to biological sensing

Abstract

Terahertz spectroscopy has long been used as an important measurement tool in fields such as radio astronomy, physical chemistry, atmospheric studies and plasma research. More recently terahertz technology has been used to develop an exciting new technique to investigate the properties of a wide range of biological materials. Although much research remains before a full understanding of the interaction between biomaterials and terahertz radiation is developed, these initial studies have created a compelling case for further scientific study. Also, the potential development of practical tools to detect and identify biological materials such as biological-warfare agents and food contaminants, or of medical diagnostic tools, is driving the need for improved terahertz technology. In particular, improved terahertz sources and detectors that can be used in practical spectroscopy systems are needed. This paper overviews some of the recent measurements of the terahertz spectra of biomaterials and the ongoing efforts to create an all-solid-state technology suitable not only for improved scientific experiments but also for military and commercial applications.

Design, theory, and measurement of a polarization-insensitive absorber for terahertz imaging

“…Specifically, the ability to perform imaging in the THz would have profound impact on the areas of security [1,2,3,4], biology [5,6], and chemistry [7,8]. However, imaging in the terahertz is complicated by the a lack of easily accessible electromagnetic responses from naturally occurring materials.…”

Numerical removal of water vapour effects from terahertz time-domain spectroscopy measurements

“…Emerging applications in non-invasive sensing are motivated by the fact that many molecules contain a rich set of characteristic resonances in this frequency range (Crowe et al 2004;Fischer et al 2007). The applications typically rely on femtosecond laser-based terahertz time-domain spectroscopy systems.…”

Terahertz optical measurements of correlated motions with possible allosteric function

“…Unfortunately these reports contained irreproducible and/or conflicting observations which likely resulted in false assignments because they did not address one chief artifact in this frequency range, namely, multiple reflection effects or Fabry-Perot etalon (Crowe et al 2004;Edwards et al 1984;Globus et al 2002Globus et al , 2006Parthasarathy et al 2005;Woolard et al 2002). Fabry-Perot etalon is an interference between copropagating light beams arising from reflections at the sample/ window surfaces.…”