The direct measurement of ablation pressure driven by 351-nm laser radiation

The instantaneous scaling of ablation pressure to laser intensity is directly inferred for ramp compression of diamond targets irradiated by 351-nm light. Continuously increasing pressure profiles from 100 to 970 GPa are produced by direct-drive laser ablation at intensities up to 7 × 1013 W/cm2. The free-surface velocity on the rear of the target is used to directly infer the instantaneous ablation-pressure profile at the front of the target. The laser intensity on target is determined by laser power measurements and fully characterized laser spots. The ablation pressure is found to depend on the laser intensity as P(GPa)=42(±3)[I(TW/cm2)]0.71(±0.01).