DescriptionThe far-infrared, or terahertz (THz) region of the electromagnetic spectrum hosts a wealth of interesting, intriguing, and highly complex interactions between radiation and matter in physical, chemical and biological systems. With photon energies in the millielectronvolt range, electromagnetic radiation at THz frequencies interacts strongly with systems that have characteristic lifetimes in the picosecond range and/or energies in the meV range. Examples of such systems include bound electrical charges, free charge plasmas, strongly confined charge plasma, excitons, transient molecular dipoles, phonons in crystalline solids, hydrogen bonds in chemicals, intermolecular forces in liquids, and biological matter. Therefore it may not be surprising that a technology that can generate and detect the amplitude and phase of electromagnetic radiation in the THz range is an invaluable spectroscopic tool for research in physics, chemistry and biology. In addition to the capability of characterizing materials in a static fashion with THz spectroscopy, and thus learn about the intrinsic dynamics of the material when exposed the THz fields, the capability to investigate ultrafast phenomena in the THz range with a time resolution of a fraction of a picosecond, while covering several decades in frequency simultaneously, will be discussed. Methods for generation, detection, and quantitative analysis of static and time-resolved THz spectroscopy will be highlighted, with emphasis on signal quality, spectral bandwidth, and reproducibility. On this basis, we will discuss spectroscopic studies of relaxation dynamics in polar liquids, phonon dynamics in molecular crystals, and ultrafast dynamics of photogenerated carriers in nanoscopic and disordered solid-state systems.
Place: Ylvæs, Finland
|3 Jun 2010 → 6 Jun 2010