The peak power of femtosecond lasers is limited by the size and damage threshold of their solid-state optical components, with the final compression grating of chirped pulse amplification systems posing a challenging bottleneck in reaching higher powers. High-power femtosecond lasers currently use reflective diffraction gratings (gold or dielectric coated) to build a compressor for chirped pulse amplification. These gratings are limited to light intensities of 1012 W/cm2, so gratings for petawatt lasers and beyond must be large to stay below the damage fluence.
This invention draws on the higher damage tolerance of plasma to manipulate high-intensity light. Plasma is a difficult medium to control and sets stringent limits on optical performance. A compact high-power laser system can be realized using plasma transmission gratings for chirped pulse compression based on currently achievable plasma properties and minimal plasma volume. A double compression architecture compensates for the low angular dispersion of plasma gratings. Design constraints can be modelled using particle-in-cell simulations of grating performance at high light intensity. These simulations suggest that the meter-scale final compression gratings for a 10-PW laser could be replaced with 2-mm-diameter plasma gratings, allowing compression to 20 fs or below with 90% efficiency for multi-petawatt (1015 W) to exawatt (1018 W) lasers.
Image Caption: Schematic of a plasma-grating-based laser system using a double-CPA architecture.
Current stage of technology development: TRL 1-2
LLNL has filed for patent protection on this invention.
U.S. Patent Application No. 2022/0376453 Plasma Gratings for High-Intensity Laser Pulse Compression published 11/24/2022
- Increases the damage fluence levels by almost 6 orders of magnitude making exawatt (1018 W) scale and beyond lasers practical.
- Enables a 1000x linear reduction of beam cross-section dimension.
- Enables a 1000x linear reduction in system size and weight by eliminating need for large fused-silica final optics.
- Intense ultrafast lasers for high energy density physics, secondary particle creation and plasma wakefield acceleration.
- Inertial confinement fusion research.
- Ultrafast X-ray radiography in medicine.
- Electron and ion beams for cancer therapy.
