Plasma Amplifiers to Enable Dramatic Increases in Laser Power and Energy to Access New Physical Processes

Project Overview

The maximum attainable laser intensity using Chirped Pulse Amplification (CPA) technology has stagnated in the last 10-15 years, with the limitation being the damage threshold of critical internal optical components. Plasma optics would be capable of withstanding 5 orders of magnitude more fluence than conventional optics if they can be implemented, but this requires a deeper understanding of the relevant linear and nonlinear plasma wave behavior. This project has enabled progress toward this goal with a variety of experimental and simulation results.

In particular, the kiloJoule laser pump energies available at the National Ignition Facility (NIF) allow study of Brillouin and other plasma scattering phenomena in a unique regime necessary to fully develop these optics. The experimental configuration here consists of "beam combination" where energy is moved from many lasers into one using the plasma environment as a transfer medium. Success was achieved in pushing this beam combination to the limits it can achieve with the beam numbers and geometries available on NIF, at which point the laser being amplified was shortened in duration to study how fast ion wave amplification impacted the resulting output beam. Experiments were also performed to amplify a beam while it was being focused, proving that the plasma transfer mechanism preserves the initial quality of the laser. Further, a series of shot days were completed to test a few materials to be used as an attenuation optic to protect NIF beamline optics from an eventual increase in pump laser power.

Mission Impact

This work has furthered LLNL goals of excellence and leadership in laser development and high energy density science and the results have been disseminated to the scientific community via a series of publications and presentations as well as a patent application. Further, the high power outputs beams developed here are of interest to several internal groups studying nuclear weapon outputs, and plans are continuing to use this platform for scaled nuclear ground effects testing ("Energy Partitioning, Energy Coupling" NIF shots in FY23) and global defense modeling improvements. As such this work will support the laboratory's nuclear deterrence mission by enhancing fundamental understanding of weapons effects and model surrogacy.

Publications, Presentations, and Patents

Kirkwood R.K. et al., "Production of High Fluence Laser Beams Using Ion Plasm Wave Optics." Appl. Phys. Lett. 120, 200501 2022.

P. L. Poole et al., "Time Resolved Measurement of Power Transfer in Plasma Amplifier Experiments on NIF," Poster presented at Conference of Lasers and Electro-Optics, Virtual. May 2021.

P. L. Poole et al., "Time Resolved Measurement of Power Transfer in Plasma Optic," Presentation at 62nd APS Division of Plasma Physics Conference. Virtual. November 2020.

R. K. Kirkwood et al., "Development of Ion Wave Plasma Optics for NIF and other Lasers," Poster presented at 62nd APS Division of Plasma Physics Conference. Virtual. November 2020.

P. L. Poole et al., "Beam Amplification to High Fluence in a Plasma Optic," Presentation at 61nd APS Division of Plasma Physics Conference, Ft. Lauderdale, FL. October 2019.

R. K. Kirkwood et al., "Ion Wave Plasma Optics Concepts for NIF and other Lasers," Poster presented at 61nd APS Division of Plasma Physics Conference, Ft. Lauderdale, FL. October 2019.

P. L. Poole et al., "Combination of up to 21 Frequency Shifted Beams with a Plasma Optic," Presentation at Anomalous Absorption Conference, Telluride, CO. June 2019.

R. K. Kirkwood et al., "Plasma Based Optical Components to Control Radiation Damage in Laser Fusion Power Applications." Patent applied for March 2022.