Single-Shot, Multi-Timestep Chirped Optical Probe Method for High Temporal Resolution Reconstruction of Plasma Evolution

Abstract

A continuing fundamental need in the field of High Energy Density (HED) and plasma physics is the accurate and precise spatial and temporal characterization of laser-plasmas as they evolve, which would provide valuable insight into the foundational physics that drive laser-plasma interactions (LPIs). LPIs are complex, rapidly evolving, and highly sensitive to shot-to-shot variations in laser parameters, such as laser peak intensity, pulse duration, pre-pulse, and focal spot, and/or thermal instabilities. Even under nominally identical laser conditions, small variations can drastically influence outcomes. However, in typical HED experiments currently, the very fast fs-ps timescales of the laser interaction and the high energy of the laser (up to kJ) can mean that measurements of parts of the interaction often must be taken prior to the actual experiment in a surrogate setup or surrogate shot. To accurately understand these interactions, on-shot experimental techniques must be developed and implemented [1,2]. This work discusses the simulation and development of a new single-frame technique for reconstruction of plasma electron density profiles at multiple (25+) timesteps within each shot using a single chirped probe pulse. This new method uses just two components, a diffractive optical element and an interference bandpass filter, to simultaneously take multiple time-resolved electron density measurements on a single camera frame.