Intense Lasers and Nanotargets – towards compact relativistic accelerators

Intense laser-plasma interactions transfer energy from laser pulses to charged particles, generating accelerated electrons and protons with energies governed by established scaling laws. Typically, laser intensities of 10¹⁶ W/cm² yield electron temperatures around 50 keV and proton energies up to 100 keV. Our recent work demonstrates that specific structural modifications to targets, combined with a low-intensity pre-pulse, can enhance electron temperatures by up to 20-fold, reaching 1 MeV, and produce electron energies up to 6 MeV—remarkable at these modest intensities. Correspondingly, proton energies of 700 keV were achieved, levels usually requiring multi-terawatt lasers. Using compact, high-repetition-rate lasers, both experimental and simulation studies revealed that linear and nonlinear parametric processes mediate energy transfer, and intense microscale field dynamics drive particle acceleration. Properties suitable for imaging, radiography and fusion were demonstrated. Surprisingly, target density profiles were found to be less dependent on structure than expected, with even sub-wavelength targets yielding similar enhancements. These findings significantly broaden the potential of compact laser systems for high-energy applications.