New Methods in High-Resolution Laser Spectroscopy

Abstract

It is not necessary any more to point out that optical spectroscopy has been revolutionized by the advent of highly monochromatic laser sources. The laser light is far superior to the light of conventional sources in brightness, spectral purity, and spatial coherence. As a result, almost all classical spectroscopic techniques become very much more sensitive and convenient through the use of lasers. In addition to the improvements of the already existing techniques, a large number of new methods, only conceivable on the basis of the laser characteristics, have been developed. It is not the aim of this chapter to give a review of all that has been done in the last 15 years. A very good review article has already been published in Part A of this monograph by Demtroder.(1) As two years have already passed since the publication of that volume, and as the developments during this period have been quite fast, it seems worthwhile to complement that work. The field of laser spectroscopy has become so wide and diverse that it is impossible to give a meaningful review of all the interesting recent advances within the limits of this presentation. We will restrict ourselves to what is now known as “high-resolution spectroscopy,” that is, the spectroscopy of the gaseous medium with a resolution better than the Doppler width of the transitions involved.