Time-resolved x-ray monitoring of laser ablation of and plasma formation from Si

Abstract
We present x‐ray absorption measurements on silicon clusters and silicon plasmas produced by pulsed laser irradiation of bulk silicon. The results are compared with earlier time‐resolved x‐ray absorption measurements on amorphous silicon foils under pulsed laser irradiation. Clusters are formed at an irradiance as low as 3.0 J/cm2. At an irradiance of 14 J/cm2 ionized species up to Si4+ are formed. We find a removed Si layer thickness of 80 Å at an irradiance of ≊6 J/cm2, at 15 ns pulse duration.