The investigation of equations of state, physical properties, and phase transitions of materials under extreme high-pressure conditions remains a fundamental challenge in condensed matter physics and planetary science. Utilizing laser-driven compression techniques, we can now replicate these extreme states in laboratory environments, achieving pressures in the terapascal (TPa) range, temperatures exceeding tens of thousands of Kelvin, and time scales spanning femtoseconds to microseconds. This capability creates a unique platform for exploring material properties under high-pressure and high-strain-rate conditions.
With the rapid advancement of next-generation large-scale laser facilities and laser-driven platforms utilizing cutting-edge X-ray sources, alongside innovative diagnostic breakthroughs, research into the dynamic responses of materials under extreme conditions not only enhances our understanding of warm dense matter but also has significant implications in fields such as astrophysics, inertial confinement fusion, national defense technology, and materials science. The development of multi-scale (macro-meso-micro) in situ diagnostic techniques, combined with multi-method detection, will provide essential support in constructing a comprehensive physical understanding of matter under extreme conditions.
This report systematically presents multi-scale diagnostic techniques based on laser-driven platforms and their applications in the study of extreme warm dense matter. At the macroscopic scale, we have developed precise measurement methods for key physical quantities such as velocity, temperature, and pressure under dynamic high-pressure conditions. At the mesoscopic scale, we have achieved in situ characterization of microcrystal sizes and pore structures. At the microscopic scale, we have made significant strides in real-time detection of lattice structure evolution. By integrating various loading methods—including shock loading, quasi-isentropic loading, and static-dynamic combined loading—we have advanced frontier issues such as establishing benchmarks for high-pressure equations of state, investigating the properties of superionic water, and elucidating the phase transition mechanisms of high-pressure carbon-based compounds. Furthermore, the report assesses the feasibility of developing multiple in situ diagnostic techniques on large-scale laser facilities. This multi-scale combined diagnostic approach offers a novel paradigm for comprehensively analyzing the physical processes of materials under dynamic loading, providing vital guidance for integrated research on material physics under extreme conditions.

[1] Zhiyu He#, Qili Zhang#, Haifeng Liu, et al., Physical Review B 103, 134107, 2021
[2] Zhiyu He, Melanie Rödel, J. Lütgert, et al., Science Advances, 8(35), 2022
[3] Zhiyu He, J. Lütgert, M. G. Stevenson, et al., High Power Laser Science and Engineering, 12, e46, 2024
[4] Zhiyu He, Xiuguang Huang, Hua Shu, et al., Chinese Journal of High Pressure Physics, 37(5), 2023

Multi-scale diagnostic techniques,in situ diognistics,equation of state; high pressure; laser