Diagnosing Intense and Ultra-intense Laser–Matter Interactions: Status and Future Requirements

Abstract

In this chapter we describe experimental techniques for investigating laser–matter interactions that have been developed in recent years within the framework of international collaborations. We introduce phenomena observed in the wide range of interaction regimes and plasma conditions, including long-scale-length plasmas, laser–plasma coupling in inertial fusion studies, and electron acceleration driven by ultrashort pluses. We focus on laser–matter interactions, particularly laser–solid interactions and laser–gas jet interactions. We also discuss in details the temporal and spatial features of laser pulses amplified by the chirped pulse amplification (CPA) technique (Strickland and Mourou, Opt. Commun. 56:212, 1986) with special attention to the properties that play an important role in laser–solid interactions, including pulse duration, contrast, prepulses and focusing configurations. We investigate plasma formation and plasma density evolution by optical interferometry techniques. We also discuss techniques for recovering information on plasma density evolution when optical interferometry with ultrashort pulses is adopted. Further, we introduce time-resolved X-ray spectroscopy of plasmas generated by ultrashort laser pulses, then we describe recent measurements of fast electron transport in solids conducted by using a novel monochromatic imaging technique. Finally, we briefly analyze some future instrumentation requirements for investigating laser–matter interaction when femtosecond laser pulses are adopted.