Stabilization of isolated attosecond pulse by controlling the emission time of high-order harmonics

Abstract

Features of an isolated attosecond pulse generated by three-color fields are investigated as a function of the time delays between different-frequency components. It is found that there is a window for the time delays in which the characteristics of an isolated attosecond pulse are relatively stable. By analyzing the variation of the driving field and the harmonic emission time with the time delays, the stability of the isolated attosecond pulse is well explained. This analysis shows that by confining the harmonic emission time in a half-cycle, the sensitivity of an isolated attosecond pulse to the shift of time delays can decrease, which is important to the ultrafast measurement with an isolated attosecond pulse.