Grant: Discovery Grants Program - Individual

Terahertz (THz) radiation, located in the deep infrared region of the electromagnetic spectrum, is increasingly used to identify molecules from their low-energy vibrational modes. In fundamental research, molecule structural dynamics have been studied with time-resolved THz spectroscopy to improve our understanding of key biological functions. In industry, THz radiation can be used to distinguish molecular compounds to enable higher quality control standards or characterize organic tissues for medical diagnostics. These various applications attest of the progress in THz systems development during the last decade. Yet, the field of THz photonics is still relatively young and, as a result, there remain many opportunities for scientific and technical innovation with a path to major discoveries. This proposal focuses on the development and application of emerging THz photonics systems to monitor and control molecules while also accessing unexplored regimes of µs dynamics and quantum interactions. The first objective aims to demonstrate a world-unique single-pulse THz spectroscopy scheme. This system is based on three areas of photonics: time-resolved THz spectroscopy, nonlinear optical interactions, and propagation in optical fibers. We will bring these techniques together in an unprecedented configuration to monitor low-energy resonances with µs resolution, a time scale impossible to access with state-of-the-art time-resolved THz systems. Furthermore, our configuration will provide a coherent set of results comparable to a slow-motion movie, allowing us to investigate phenomena occurring only a single time before irreversible changes in the sample The second objective focuses on the application of the single-pulse THz system to deepen our understanding of protein dynamics and shed light on the fundamental question of how enzymes evolve throughout their catalytic cycles. To our knowledge, this will be the first attempt at exploring fast modulations of enzyme vibrational modes following excitation of their intrinsic conformational dynamics. These results will complement those obtained with time-resolved temperature-jump x-ray crystallography and allow us to correlate observed changes in the enzymes' vibrational modes with global and local changes to their atomic structures. The last objective focuses on vibrational polaritons, a quantum particle created when the vibration mode of a molecule is strongly coupled with a resonant THz mode within a confined volume. We will use metasurfaces with THz plasmonic resonances and select proteins displaying a single prominent THz resonance, such as glucose and lactose, to reach this strong coupling regime. Finally, we are mostly interested in studying changes induced to the molecules' optical absorption properties due to the hybridization process of the vibrational states. This research could lead to a new generation of sensors harvesting quantum superposition of molecular resonances with THz plasmonic modes.