This Encyclopedia aims, basically, at summanzmg the wealth of well established facts and outlining the relevant theories in the different branches of physics. With this as goal, the writers were asked to present their specific field in such a way that access is possible to any scientist without special a priori information in that field; the basic concepts of physics are assumed to be known to the reader. The survey given in each paper was also to be long lasting, so that even a few years after publication, each volume would be useful, for example as an introduction for newcomers or as a...

In 1986, an International Symposium on Monitoring of Gaseous Pollut- ants by Tunable Diode Lasers was organized by the Fraunhofer-Institut fuer Physikalische Messtechnik in Freiburg, FRG, and held at this institution on November 13-14, 1986. The papers presented at that occasion extensively covered the applications of tunable diode laser spectroscopy (TDLS) to the analysis of trace and exhaust gases together with the latest improvements brought to the tech- niques used. It was generally consented by the participants that meetings of this kind are of major importance and should take place on a...

By now it has been nearly twenty years since the pioneering studies at the MIT-Lincoln Laboratories, Lexington, USA, demonstrated the unique capabilities of lead salt tunable diode lasers (TDL) for infrared absorption spectroscopy. The progress in the use of TDL instrumentation for a wide variety of scientific applications was described by a great number of papers since, however, comparatively few meetings were specifically devoted to this subject. In 1980 the conference on "High Resolution Infrared Spectroscopy Applications and Developments" at the National Bureau of Standards in...