Microwave and terahertz spectroscopy

Spectroscopy, or the study of the interaction of light with matter, has become one of the major tools of the natural and physical sciences during this century. As the wavelength of the radiation is varied across the electromagnetic spectrum, characteristic properties of atoms, molecules, liquid and solids are probed. In the optical and ultraviolet regions (λ ~ 1 µm up to 100 nm) it is the electronic structure of the material that is investigated, while at infrared wavelengths (~ 1-30 µm) the vibrational degrees of freedom dominate.