Multichannel Doppler fiber-imager spectrometer for spatio-temporal characterization of high-intensity laser-driven plasmas

Abstract

We demonstrate a flexible multichannel fiber-based imaging Doppler spectrometer to characterize plasmas in high intensity (≥1 × 10¹⁸ W/cm²) laser-plasma experiments at high repetition rates. This instrument collects data from ×21 different plasma locations combining optical fibers and a single imaging spectrometer. This diagnostic maps the plasma velocity evolution as a function of time with sub-pico-second resolution. Experimental results showing 2D velocity measurements of plasma with 20 μm spatial resolution are presented. Intensities of the order of 10<sup<18 W/cm² were used to generate a plasma, while a much less intense, frequency doubled (400 nm), probe beam (10¹¹ W/cm²) was used to measure the Doppler shift from the plasma critical surface. The instrument can be scaled to a larger number of channels (e.g., 100) still using a single spectrometer.

DOI: https://doi.org/10.1063/5.0200285