Introduction

Abstract

The current interest in the use of lasers, be it for scientific investigations or for industrial applications, is directly linked to the unique properties of laser light. The high spatial coherence achieved with lasers permits extreme focusing and directional irradiation at high energy densities. The monochromaticity of laser light, together with its tunability, opens up the possibility of highly selective narrow-band excitation. Controlled pulsed excitation offers high temporal resolution and often makes it possible to overcome competing dissipative mechanisms within the particular system under investigation. The combination of all of these properties offers a wide and versatile range of quite different applications.