This paper describes a set of demonstration school experiments where infrared radiation is detected using thermal sensitive foils. The possibility of using standard glass lenses for infrared imaging is discussed in detail. It is shown that with optic components made from glass, infrared radiation up to 2.5 µm of wavelength can be detected. The…

Discusses how the frequency domain (line widths) and time domain (coherent optical transients) are related to the concept of transverse relaxation time in the study of high resolution optical spectroscopy. (HM)