The combination of polarization gating and two-color gating is a promising approach to generate single isolated attosecond pulses with multicycle pump lasers. We searched the phase-matching conditions for high-order harmonic generation with such a double optical gating using $0.85\mathrm{mJ}$, $8\mathrm{fs}$ laser pulses centered at $790\mathrm{nm}$. At the optimized gas target location and pressure, the single extreme ultraviolet pulse energy is $6.5\mathrm{nJ}$ for argon and 170 pJ for neon, which are much higher then those generated with conventional polarization gating. In addition, the carrier-envelope phase effects with a $2\pi$ periodicity were attained when the highest extreme ultraviolet photon flux was produced, indicating the robustness of the double optical gating.

• Received 3 April 2008

DOI:https://doi.org/10.1103/PhysRevA.77.063423