Nanosecond Time Resolved Reflectivity Measurements At the Surface of Pulsed Laser Irradiated Graphite

Time resolved reflectivity measurements at the surface of pulsed laser irradiated graphite are found to be complicated by the evolution of carbon atoms from the surface which attenuates the probe beam. The evolution of the species occurs concomitant with the observation of the melt on a time scale of <2 nsec. Further, the emitted species have velocities of:≤ 2 × 105 cm/s. The experimental results suggest the formation of large clusters at the molten surface though more experiments are required to clearly distinguish the effect of clusters from those due to the formation of a randomly reflecting plasma.