Plasma optics for compression of ultraintense laser pulses

M.S. Hur

Exawatt or zettawatt laser pulses can be groundbreaking scientific tools for uncovering the mysteries of our universe. These high-power laser pulses enable experimental studies of phenomena such as vacuum boiling and pair-production, Hawking radiation, and quantum gravity, holding great potential for advancing our understanding of nature. However, the currently available CPA technology is stuck at petawatt level, mainly due to the material breakdown of compression gratings and alternative solutions are yet to come from conventional optics. Plasma, being in a state of matter already broken down, can endure highly intense laser fields without damage. Its resilience to strong fields, coupled with its optically dispersive properties, makes plasma an ideal medium for manipulating high-power laser pulses. In this presentation, I will present a recently devised novel concept for pulse compression using a density gradient, high density plasma. The point of the new idea is generating reflection path difference of photons of a chirped pulse using a near-critical, gradient densit plasma. As the higher frequency photons take longer reflection path deeper into the plasma, the photons in the tail of a negatively chirped pulse can catch up those in the pulse front, resulting in concentration of the photons into a narrow region. So far this idea is still in theoretical and modelling level, but it has been already published to Nature Photonics in 2023 [1], and experimental proof-of-principle is in progress. In theoretical point of view, combining different plasma optics ideas with the original density gradient idea is being studied. Here I present the status of the research and future vision of this innovative concept, providing comparison of characteristics of previous plasma-based schemes such as Raman, Brillouin and plasma gratings. These advancements can be crucial steps toward realizing compact, exawatt, or zettawatt laser pulses. [1] Hur et al., Laser pulse compression by a density gradient plasma for exawatt to zettawatt lasers, Nature Photonics 17, 1074 (2023).