Overcritical to Underdense Plasma in Under 1 $\mu \hbox {m}$ : 150 TW Laser–Thin-Target Interactions for Particle Acceleration

When a high-intensity laser interacts with a solid target, a well-known phenomenon, namely, the production of multimegaelectronvolt particles, occurs. However, if the laser and target thickness are carefully chosen to coincide with the burn-through of the laser´s amplified-spontaneous-emission prepulse, the main pulse of the laser can interact with a short-scale-length near-critical-density plasma, and a very low divergent electron beam can be produced.