Selective bond breaking of CO in phase-locked two-color intense laser fields: laser field intensity dependence.

Selective bond breaking of CO in phase-locked ω-2ω two-color intense laser fields (λ = 800 nm and 400 nm, total field intensity I ∼ 10 W cm) has been investigated by coincidence momentum imaging. The CO and O fragment ions produced by two-body Coulomb explosion, CO → CO + O, exhibit asymmetric distributions along the laser polarization direction, showing that one of the two equivalent C-O bonds is selectively broken by the laser fields. At a field intensity higher than 2 × 10 W cm, the largest fragment asymmetry is observed when the relative phase ϕ between the ω and 2ω laser fields is ∼0 and π.