Abstract

Although there have been a number of theoretical and experimental investigations of the nature of carbon,^1–3 uncertainty remains about even for its most basic electronic properties, particularly in its liquid phase. We investigate the ultrafast dynamics of crystalline carbon (graphite and diamond) when optically excited over a wide range of pump fluences. The motivation for this is twofold. At fluences above the critical melting fluence, it is possible to create liquid carbon from both graphite and diamond and study its conductivity, which has been debated in recent literature. At fluences well below and approaching the critical melting threshold, the ultrafast carrier generation, relaxation, and recombination in crystalline graphite can be investigated, a subject of which little is known even though graphite has served as a textbook system for fundamental investigations of solid state physics for over fifty years.⁴

© 1990 Optical Society of America