Seminar Romain Peretti

Université de Lille

Terahertz Spectroscopy and Its Applications Towards Biology  

Terahertz (THz) spectroscopy, situated between the microwave and infrared regions of the electromagnetic spectrum, has seen significant advancements since the mid-1990s, driven by developments in optoelectronics and femtosecond laser technologies. In this seminar, I will present an overview of THz spectroscopy, focusing on its potential for biologically relevant applications. I will begin by discussing the technologies behind THz spectroscopy, particularly time-domain spectroscopy (TDS), its setup, and limitations. I will then outline results across the three states of matter. In the gaseous phase, I will highlight its potential for detecting organic volatile compounds, relevant to health and agriculture. In the liquid phase, I will discuss the challenges posed by water dynamics at the picosecond scale. Finally, in the solid phase, I will show how THz spectroscopy probes polymorphism in molecular crystals and explores phonon polaritons, including Mie polaritons in calcite aerosols with implications for global climate, and polaritonic modes in lead iodide (PbI₂) crystals, where we observed the most compressed polaritonic wavelengths. This overview will demonstrate how THz spectroscopy addresses challenges in biology, health, and environmental science.