Investigating Physical Systems with Optical Spectroscopy

Abstract

The article is based on the lectures that I delivered at the beginning of the course “Frontiers of Optical Spectroscopy,” a NATO Advanced Study Institute that took place at the Ettore Majorana Center in Erice, Italy, May 16 – June 1, 2003.

The purpose of this contribution is to present some background material useful to deal with the application of optical spectroscopy to the study of physical systems.

In the introductory lecture we differentiate between two cases of “extreme physical conditions”:

• i) extreme conditions that predate experimentation, having been produced artificially and objectively different from more common ones, and

• ii) extreme conditions created by an experimenter who employs some technical procedure to vary or modify the status of some systems and bring them into conditions different from their natural ones.

In the second lecture we treat the interaction of radiation with atoms and molecules. We introduce the concept of transition rate. In addition, we deal with the optical Bloch equations, the Rabi oscillations, and the mechanisms responsible for the broadening of spectral lines.