Ultrafast lasers for attosecond science

The first measurement of attosecond pulses in 2001 unleashed a new wave of exploration in the microcosmic world. The pulse width has since shrunk from an initial 650 to 43 as, and the flux, photon energy, and repetition rates have progressively been raised. The performance of attosecond pulses hinges upon the driving lasers, whose rapid development underlaid many advancements of attosecond technology. Yet the expansion of new applications in attosecond science demands driving lasers with ever better performance. Beginning with the fundamental principles of attosecond pulse generation and applications, this article reviews the evolution and trend of the driving lasers in terms of pulse energy, pulse width, wavelength, and repetition rate.