The 6th International Conference on Matter and Radiation at Extremes (ICMRE2023)

104 / 2023-04-13 21:15:53

Extreme focusing of high-power X-ray laser based on solid-density plasma

X-ray Laser,Plasma Optics,Structured Target,Relativistic Intensity,Self-focusing

Radiation and Hydrodynamics > High energy density science and warm dense matter-I

Intense X-ray lasers offer exceptional properties that are valuable for a wide range of applications. To achieve multi-TW of X-ray pulses, numerous methods have been proposed for free-electron laser facilities. Additionally, high-harmonic generation from solid surface plasma can theoretically produce a single X-ray pulse using modern lasers. However, the focal spot sizes of these X-ray sources are typically large, reaching up to hundreds of micrometers, limiting the range of exploration in science. Furthermore, current optical technology can focus hard X-rays to less than 10 nm, but the focal size is still approximately two orders of magnitude higher than the wavelength. There is still no efficient way to focus high-power X-ray lasers.



In this presentation, we propose the use of solid-density plasma to focus high-power X-ray pulses at TW levels. We demonstrate that there is a range of wavelengths that can be focused when the input power and plasma density are determined. However, X-ray pulses with micrometer-sized large spots suffer from disruptive multi-dimensional instabilities when propagating in plasmas, making it challenging to focus high-power X-rays using solid-density plasmas. To solve this issue, we propose the utilization of a well-designed concave plasma lens to generate an extremely intense X-ray laser. Our approach effectively realizes X-ray focusing at TW levels while circumventing instabilities caused by laser-plasma interactions. Three-dimensional particle-in-cell simulations further demonstrate that immense spatiotemporal profiles can be maintained while achieving peak power density hundreds of times higher than the relativistic threshold. This breakthrough allows for unprecedented opportunities to investigate unexplored phenomena in the X-ray region and to advance the development of strong-field quantum electrodynamics, astronomical physics, and high-energy-density science.