Towards The Exawatt Class Laser: A New Concept for the Next Generation Ultra-Intense Laser
Researchers from Osaka University proposed the concept of a next-generation ultra-intense laser, likely increasing the current record from 10 Petawatt to 500 Petawatt.
Ultra-intense lasers with ultra-short pulses and ultra-high energy are powerful tools for exploring the unknown in physics, cosmology, material science, etc. With the help of the well-known technology “Chirped Pulse Amplification (CPA)” (2018 Nobel Prize in Physics), the current record has reached 10 Petawatts (or 10^16 Watts). In a study recently published in Scientific Reports, researchers from Osaka University proposed the concept of a next-generation ultra-intense laser with peak power simulations up to the Exawatt class (1 Exawatt equals 1000 Petawatts).
The laser, discovered by Dr. TH Maiman in 1960, has one important characteristic with high intensity (or high peak power for pulsed lasers): historically, laser peak power has undergone two stages of development. Right after the birth of the laser, Q-switching and mode-locking technology increased the laser’s peak power to kilowatt (10^3 Watt) and Gigawatt (10^9 Watt) levels. After CPA technology was discovered by Gérard Mourou and Donna Strickland in 1985, where material damage and nonlinear optics could be avoided, laser peak power was dramatically increased to terawatt (10^12 Watt) and Petawatt (10^15 Watt) levels. Today, two 10-Petawatt CPA lasers have been demonstrated in Europe (ELI-NP laser) and China (SULF laser), respectively.
Today, the scale of Petawatt laser facilities around the world is huge and project investment is also very high. The next step for future ultra-intense lasers is to increase peak power further by compressing the duration of the pulse instead of increasing the pulse energy.
In their previous study (OSA Continuum, DOI: 10.1364/OSAC.2.001125), the group developed a new design, “Wide-angle Non-collinear Optical Parametric Chirped Pulse Amplification (WNOPCPA),” to enhance the reinforced spectrum and therefore reduce compressed pulses. The key mechanism of WNOPCPA is to increase overall bandwidth by using dual beam pumps, which correspond to different reinforced spectrums. “However, pump disruptions, in addition to the possibility of damage caused, are potential problems in the application of WNOPCPA to major projects,” explained author Zhaoyang Li.
In this newly enhanced design, using wnopcpa pumped two files and carefully optimized phase matching, pump interference is completely avoided, and ultra-broadband bandwidth with two broad spectrum is achieved, resulting in high energy laser amplification <10 fs. When this laser is combined with post-compression technology, the spectral dilation caused by nonlinener effects is significantly improved, and simulations show the highest peak power records that can be driven to the Exawatt class.
“This design has two advantages: one is ultra-broadband amplification in WNOPCPA and the other is an increase in nonliner spectral widening in post-compression. This research could provide a possible way to further increase the peak power of the laser, even up to the Exawatt class,” said Zhaoyang Li.