For this thesis a new method for using terahertz spectroscopy to simultaneously measure density and moisture content in wood was tested for potential commercial use. Generally terahertz spectroscopy systems are nonviable for commercial applications due to the expense and complexity of most terahertz systems. However, simple and less expensive terahertz interferometer systems could be applicable if the phase and amplitude measurements of such a system could predict the density and moisture content just as well as other terahertz systems. As such, using a single frequency source in an interferometer configuration the phase and amplitude measurements are quantitatively evaluated to simultaneously predict density and moisture content. Medium density fiberboard is studied using the system and compared directly to tera¬ hertz time-domain spectroscopy measurements, demonstrating that both systems are able to achieve simultaneous prediction of density and moisture content. Therefore, it has been demonstrated that terahertz non-destructive evaluation of wood products, which requires expensive and complicated equipment, can also be performed using inexpensive single frequency sources and detectors suitable for use in industry today.
