The realm of ultra-intense ultrashort lasers holds immense promise across various fields such as basic physics, national security, industrial services, and healthcare. These lasers have revolutionized research in strong-field laser physics, including laser-driven radiation sources, laser particle acceleration, and vacuum quantum electrodynamics. Over the years, the power of these lasers has surged dramatically, with peak laser power peaking at 10-petawatt in recent advancements. However, the upper limit for titanium:sapphire ultra-intense ultrashort lasers seems to plateau at 10-petawatt. Efforts are now being made to push the boundaries further and achieve 10-100 petawatt laser power through alternative technologies. In this article, we explore the limitations of current technology and a groundbreaking solution that involves coherently tiling multiple titanium:sapphire crystals.
Titanium:sapphire chirped pulse amplification has been a mature technology, enabling the realization of two 10-petawatt lasers in China and Europe. The titanium:sapphire crystal, an energy-level-type broadband laser gain medium, facilitates the storage and amplification of energy from a pump pulse. However, one major challenge faced with this technology is transverse parasitic lasing, where amplified spontaneous emission noise along the crystal diameter disrupts the stored energy and reduces signal laser amplification.
The current maximum aperture of titanium:sapphire crystals is limited to supporting 10-petawatt lasers. Even with larger crystals, strong transverse parasitic lasing escalates exponentially, making laser amplification unattainable. This limitation poses a significant roadblock in the development of ultra-intense ultrashort lasers beyond the 10-petawatt mark.
In a recent groundbreaking development reported in Advanced Photonics Nexus, researchers have successfully tackled the 10-petawatt limitation by coherently tiling multiple titanium:sapphire crystals together. This innovative approach significantly increases the aperture diameter of the entire crystal assembly while simultaneously restraining transverse parasitic lasing within each tiling crystal.
Lead author Yuxin Leng from the Shanghai Institute of Optics and Fine Mechanics expresses their excitement, stating, “The tiled titanium:sapphire laser amplification was successfully demonstrated in our 100-terawatt (i.e., 0.1-petawatt) laser system. We achieved near-ideal laser amplification using this technology, including high conversion efficiencies, stable energies, broadband spectra, short pulses, and small focal spots.”
Unlocking the Potential: Advantages and Implications
The coherently tiled titanium:sapphire laser amplification offers a remarkable opportunity to surpass the current 10-petawatt limit in a relatively easy and cost-effective manner. By incorporating a 2×2 tile configuration into existing setups like China’s SULF or EU’s ELI-NP, the laser power can be increased to 40-petawatt, with the focused peak intensity rising by nearly tenfold or more. This breakthrough method holds tremendous promise in enhancing the experimental capabilities of ultra-intense ultrashort lasers for the thriving field of strong-field laser physics.
The development of ultra-intense ultrashort lasers has unlocked endless possibilities across various domains. While the current technology using titanium:sapphire crystals has reached its limitations at 10-petawatt, researchers are striving for even more powerful lasers in the 10-100 petawatt range. The utilization of coherently tiled titanium:sapphire crystals has emerged as a revolutionary solution to break free from the constraints of transverse parasitic lasing. By expanding the aperture diameter and mitigating energy loss, this novel approach promises to unlock the full potential of ultra-intense ultrashort lasers and revolutionize the realm of strong-field laser physics.