In this proposal, we seek Follow-on funding to support the technical and commercial development of a cheap highly portable terahertz (THz) frequency time-domain spectrometer that will, within a five year timescale, reduce both the cost and size of such instrumentation by a factor of >10. The IP which we will exploit is the generation and detection of terahertz radiation from a new material (iron-doped indium gallium arsenide, Fe-InGaAs) which is showing tremendous potential for integration with relatively cheap telecoms wavelength lasers, which we developed using a recent EPSRC grant (PORTRAIT; EP/D50225X/1). We have protected use of this material for THz spectroscopy by a recent GB patent application (GB 0912512.1), and now seek to commercialize our results in order to push the wide-scale uptake of THz spectroscopy systems across a broad range of application areas, which include (but are not restricted to) the pharmaceutical, security, process monitoring, and medical sectors. In each area, there have been extensive demonstrations (by both academia and industrial R&D laboratories) of the potential impact of THz spectroscopy, but the keys factors of price and lack of portability have so far limited commercial uptake. Our new material allows efficient THz emission using cheap and highly portable (1.55 micron) fibre lasers. We have shown that it is possible to construct fibre-coupled THz emitters and detectors using our material which offer greater flexibility and enhanced performance compared to existing technology. We now seek to create optimized prototype THz emitters and detector components, based on our recently patented new material, which will be appropriate for widespread applications of THz frequency range sensing across many sectors.Terahertz time-domain spectroscopy (THz-TDS) systems have wide-scale applicability, especially for the measurement of polycrystalline powders, which typically have characteristic fingerprint spectra in the THz frequency range. THz spectroscopy and imaging systems thus offer the possibility of non-contact characterization and monitoring of a wide range of materials, which include pharmaceutical drugs, drugs-of-abuse, and explosives, inter alia. We are targeting the pharmaceutical market during the Follow-on funding period, owing to the established use of THz technology there. THz-TDS is proven to have importance in the pharmaceutical industry owing to its ability to distinguish polymorphic forms, and the ability to penetrate tablet coatings and packaging. Furthermore, it provides complementary information to other vibrational spectroscopic techniques, particularly Raman spectroscopy, owing to the different selection rules governing which normal modes are observed. The US Food and Drug Administration guidance for pharmaceutical development, manufacturing, and quality assurance has explicitly placed process analytical technologies, such as THz-TDS, as central to innovation in pharmaceutical manufacture over the coming decade.