Attosecond-magnetic-field-pulse generation by electronic currents in bichromatic circularly polarized UV laser fields

Attosecond-magnetic-field-pulse generation is simulated from numerical solutions of time-dependent Schrodinger equations for oriented H-2(+). Two schemes with high frequency co- and counter-rotating bichromatic omega(2) = 2 omega(1) circularly polarized UV laser pulses are investigated. Results show that comparing to single color processes, stronger induced localized magnetic fields B at the molecular center O (r = 0) are obtained with attosecond duration. This is attributed to frequent recollision and to interference effects of two pathways in photoionization. The induced magnetic fields are shown to be sensitive to (i) the helicity of the combined laser pulses due to different recollision laser-induced electron trajectories and currents, and (ii) also the carrier envelope phases of the combined attosecond laser pulses. The sensitivity of recollision to bichromatic pulses thus allows one to control the induced magnetic-field-pulse generation.