Grant: Discovery Grants Program - Individual

Terahertz (THz) frequencies are widely regarded as the last frontier of the electromagnetic spectrum because access to these frequencies remain the least mature, despite important applications in security, non-destructive evaluation (NDE), and biomedical imaging. THz technology is promising because most dry, non-conductive materials are transparent at these frequencies and sub-mm wavelengths enable imaging features of interest. Unlike X-rays, THz radiation is non-ionizing, posing no health concerns. Uniquely, THz can probe composite materials because fibre orientation in fibrous composites can be imaged or measured enabling powerful new techniques for quality control in new composite materials, for example in aerospace engineering. The ultimate utility of THz technology is therefore in areas where (i) safety, (ii) transparency, (iii) spatial resolution and (iv) physical structure all need to be accessed simultaneously. Even though enormous potential has been demonstrated, industry adoption of THz technology is limited because of cost and speed of THz systems, and fundamental gaps in our knowledge of THz-matter interactions. For example, the interaction of THz with water in cellulose networks is poorly understood despite water playing a critical role in wood and engineered wood products and the knowledge-gap limits the areas in which THz technology can solve problems in wood manufacturing. Moreover, as technology yields high-intensity THz sources, there is a great opportunity to look at driving materials with exceptionally high THz field amplitudes. Indeed, nonlinear interaction of sub-cycle electromagnetic radiation with matter is at the current frontier in ultrafast nonlinear optics and high-field physics. The research proposed here addresses [1] challenges with existing THz systems limiting speed so that [2] new areas of application of the technology can be developed suitable for industrial settings and commercial development and [3] the need to further fundamental science in THz-matter interactions for next-generation technology. This will be accomplished by [1] developing polarization-resolved single-pixel imaging for the first time, [2] developing real-time THz phase-contrast imaging on a mock manufacturing line for simultaneous measurement of density and moisture content in engineered wood products enabled by [3] filling-in knowledge gaps related to THz-water interactions within wood products and exploring newly accessible regimes of high-field THz-matter interactions. The results of the research will advance knowledge, generate valuable intellectual property, and advance state-of-the art in THz applications, enhance innovation and industry adoption in the wood products industry, and generate new technologies relevant to the photonics industry broadly - industries which are economically important in Canada.