RII Track-4: Experiments on a High Intensity, Coherent Plasma Laser through Stimulated Raman Backscattering

Delaware State University, Dover DE

Investigators

Abstract

Nontechnical Description A laser (Light Amplification by Stimulated Emission of Radiation) is essentially an amplifier, whose operation depends on pumping energy into the electrons of atoms in a gas, liquid, or solid substance called the lasing medium. The production of very high-power (on the order of a few billion watts), ultra-short (a few billionth of a second) laser pulses places stringent demands on the lasing medium. Scientists have used elegant optical techniques and plasmas (ionized gas) that can operate at extreme intensities to develop high-power pulsed lasers. However, further advancement requires understanding processes within the amplifying medium and overcoming technological challenges that limit the output power. This project focuses on achieving increased output power of plasma based ultrafast lasers by combining the expertise and instrumentation available at Delaware State University with those of the Lawrence Livermore National Laboratory (LLNL). The fellowship grant from the National Science Foundation (NSF) Established Program to Stimulate Competitive Research (EPSCoR) provides the Principal Investigator (PI) and her students the support needed to pursue an integrated effort involving experiments, theory, and simulations. The project offers a unique opportunity for an early career researcher and students from Delaware State University, a member of the Historically Black Colleges and Universities (HBCU), to train at a premier national facility in building a table-top high-power plasma laser. Technical Description The goal of this EPSCoR Research Fellowship is to achieve ultrashort (20-30 femtosecond) pulses at petawatt/exawatt/zettawatt peak power in a table-top plasma-based laser. The experiments will use Stimulated Raman Backscattering (SRBS), in which amplification of a seed laser pulse power occurs via excited plasma Langmuir waves in a configuration of counter-propagating pump and seed beams. The seed laser will be shipped from Delaware State University and the experiments will be performed at the Lawrence Livermore National Laboratory (LLNL) using a pump laser available at LLNL's Jupiter Laser Facility (JLF). The project involves the installation of the seed laser, development of a plasma waveguide and studies of its characteristics, implementation of a single stage SRBS experiment pumped by a JLF laser, and finally a two stage (two gas jets) experiment. These experiments will explore the saturation mechanism predicted by the particle in cells (PIC) simulations by the PI's group and use an integrated effort that combines theoretical analysis, simulations, and experimental investigation to address the peak power saturation in plasma-based high-power lasers. The project provides a unique opportunity for the PI and her students to combine home institution's instrumentation with those available at large scale national facilities to conduct experiments that are guided by theory and simulation, and in turn provide useful feedback to validate and help improve theoretical models. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.