The PW laser system at CoReLS will be continuously upgraded to obtain the highest laser intensity. Achieving a ultrahigh laser intensity is a challenging task that requires cutting-edge laser technologies, such as highly efficient broadband amplification, contrast enhancement, wavefront control, and tight focusing techniques. The ongoing development of laser technologies is essential for sustaining excellence in research activities.

We investigate the interactions between super-intense laser pulses and under-dense plasma to produce multi-GeV electron beams through Laser Wakefield Acceleration (LWFA). The high-energy electron beams can be used to generate unique (highly bright, ultra-short, spectrally narrow) high-energy radiations (X-ray or γ-ray), which can be powerful tools for nanomaterial and biomaterial research in ultrafast timescales. The low density laer-plasma group has intensively worked on nonlinear Compton scattering between a multi-GeV electron beam and an ultrahigh intensity laser pulse to reveal strong field quantum electrodynamic processes.

We conduct research on the generation of protons/ions with the energy of several hundred MeV by applying super-intense laser pulses to ultrathin solid targets and exploring underlying physical mechanisms. The realization of radiation pressure acceleration for protons/ions is important because energetic proton/ion beams can be produced in an efficient way. Energetic proton/ion beams can be used as new imaging tools for matter under extreme physical conditions and for novel laser cancer-therapy machines.

Attosecond (10^-18s) light pulses can be produced from gaseous and solid targets irradiated by ultra-intense laser pulses through high harmonic generation. The physical conditions for extending high harmonic orders to support attosecond and even zeptosecond (10^-21s) pulses are being investigated. Ultrafast physical processes in atoms, molecules, and plasmas can be explored using attosecond pulses. In addition, the generation of zeptosecond pulses will make it possible to investigate nuclear dynamics. Such research should expand new horizons in ultrafast optical science and advance our understanding of ultrafast phenomena.

Ultra-intense lasers lead us to an unexplored territory of physics, to which other terrestrial means cannot. Upon impinging on a material, an ultra-intense laser field immediately turns the material into a plasma exhibiting novel phenomena, such as collective relativistic plasma motions, strong radiation reaction effects, and nonlinear quantum electrodynamic processes. The dynamics in such a physical system is highly nonlinear, couples multiple frameworks of physics (classical electrodynamics and quantum electrodynamics), and is embodied through the processes at multiple spacetime scales. Understanding the new physics of such extreme conditions and utilizing it for other scientific or technological purposes has been a highly fascinating research opportunity for the last two decades.

The group investigates the physics problems in ultra-intense laser-plasma interactions by performing particle-in-cell and hydrodynamic simulations. The group also closely collaborates with the experimental groups by proposing new schemes, numerically testing experimental setups, and interpreting experimental results.

High energy density (HED) science is defined as the study of matter at extreme radiation, pressure, and temperature corresponding to energy densities in excess of about 10¹¹ J/m³. HED conditions are widespread in the universe and in laboratories. Within the regime of HED states, warm dense matter (WDM) represents the state in which the thermal energy is comparable to the Fermi energy and ions are strongly coupled. With recent development of high power lasers and x‐ray light sources, quantitative physics experiments such as creation and diagnosis of a single-state WDM became feasible in laboratory. Taking such advantages, the HEDP group has been working on electronic structure of WDM, EOS, opacity, energy transport in HED matter, fusion cross section, pair-production, development of advanced x-ray diagnostics and has plans to investigate further for deeper understanding of fundamental properties of matter under high energy density conditions.