Abstract
We propose a new scheme of attosecond pulse generation by starting from a narrow-band transform-limited high-power solid-state laser and phase lock the fundamental and its first four cascaded harmonics generated by the second-order nonlinear optical processes. The relative phase among the optical fields of the harmonics can be maintained a constant at least for thousands of nanosecond pulses. The worst-case relative phase fluctuation is 0.04π rad. It is shown that sub-single-cycle (~0.37 cycle) sub-femtosecond (360 attosecond) pulses with carrier-envelope phase (CEP) control can be generated in this manner. The peak intensity of each pulse exceeds 10 14 W/cm 2 when it is focused to a spot size of 20 μm. We also demonstrate synthesis of square and saw-tooth waveforms. © 2012 by Astro Ltd., published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA.