Controlled directional ion emission from several fragmentation channels of CO driven by a few-cycle laser field

We explore the dissociative ionization of CO with carrier-envelope-phase (CEP) tagged few-cycle laser pulses. We observe the CEP dependence of the directional emission of Cᵖ⁺ and Oq+ fragments from transient CO(p+q)+ ions, where p+q≤3 and q≤1. At I₀=3.5×10¹⁴ W/cm², a 180^∘ phase difference between the C⁺ and O⁺ fragments from the ($p=1$, $q=0$) and ($p=0$, $q=1$) channels reflects the orientation dependence of the CO ionization. At I₀=1.2×10¹⁵ W/cm², we find a ~35^∘ phase shift between the C²⁺ fragments from the ($p=2$, $q=0$) and (p=2,4pt0exq=1) channels, in contrast to the 180^∘ shift previously observed between the C²⁺ fragment channels at I₀=6×10¹⁴ W/cm² [Phys. Rev. Lett. 106, 073004 (2011)].