Experimental implementation of a strong two-color asymmetric laser field in the mid-infrared

We report the experimental implementation of a strong two-color (omega/2 omega) asymmetric laser field in the mid-infrared regime (MIR) consisting of a fs pulse centered at 1400 nm and its second harmonic (700 nm). Control of the temporal delay between the two pulses with sub-cycle accuracy and, therefore, the two-color field phase is based on the use of a birefringent calcite plate. The experimental methodology is described in detail for the 1400/700 nm case, while its applicability is discussed for a broader wavelength range, nowadays accessible by optical parametric amplifiers. The validity of the proposed methodology is further supported by the application of the asymmetric 1400/700 nm field on the dissociative ionization of carbon monoxide, which is considered to be a benchmark target in the field of coherent control of strong laser-matter interaction. It is demonstrated that efficient control on the directional emission of the CO ionic fragments is achieved by varying the relative phase of the 1400 and 700 nm field components.