Generation of isolated attosecond pulses by polarization gating of high-order harmonic emission from H-2(+) in intense ultrashort laser fields

摘要

This study presents a quantum-mechanical investigation of single attosecond pulse generation by gating high-order harmonic emission from H-2(+) molecules in intense laser pulses with time-dependent ellipticity. The high-order harmonic generation from H-2(+) molecules under left-and right-hand circularly polarized Gaussian pulses in superposition, is studied, and the effect of time duration and carrier-envelope phase of laser field on single attosecond pulse generation is investigated. Using a laser field formed by combination of left-and right-hand elliptically polarized Gaussian pulses, the effect of ellipticity of field on the duration and intensity of the attosecond pulses generated is studied. Numerical calculations show that, with the conventional polarization gating, a single attosecond pulse can be isolated from the pulse train emitted by the H-2(+) molecule in a laser field.