Single Attosecond Extreme Ultraviolet Pulse Source via Light-Wave-Controlled Relativistic Laser–Plasma Interaction: Thomson Backscattering Scheme

Reflecting light off a mirror moving near light speed offers a powerful method for generating bright, ultrashort pulses in the extreme ultraviolet range. Several investigations show that dense relativistic electron mirrors can be created by striking a nanometer-scale foil with a high-intensity, sharp-fronted laser pulse, forming a single relativistic electron sheet (RES). This RES coherently reflects and upshifts a counterpropagating laser beam from the infrared to the extreme ultraviolet with efficiency exceeding incoherent scattering by over several orders of magnitude. Here, we demonstrate that optimizing the drive laser waveform can reliably produce a single RES, leading to the generation of isolated attosecond pulses enhancing both the intensity and temporal compression of the back-reflected light in a controlled manner. Simulations reveal that tuning parameters like timing delay enables control over the amplitude, duration, and bandwidth of the resulting attosecond Thomson backscattering pulse. Together, these advances meet key experimental challenges and pave the way for compact, tunable sources of isolated attosecond pulses for probing ultrafast phenomena.