Ultrafast photodissociation assisted by strong non-resonant Stark effect: the ‘straddling’ control pulse

Abstract

Control of the ultrashort photodissociation dynamics of a diatomic molecule on different excitation channels is investigated by Stark shift with a strong and approximately constant electric pulse, that ‘straddles’ the pump pulse excitation. The scheme implies first the creation of the light-induced potentials (LIP) in the presence of the control field, then the selective crossing to a single excited LIP by the ultrashort pump pulse, and finally the turn-off of the control field. We observe: (1) blue-shifting of the photospectra controlled by the field amplitude; (2) non-selective photodissociation of a single exit channel in all the interval of energies despite selective adiabatic passage of the wave packet and some control of the branching ratio; (3) high yields of population transfer to weakly bonded states in the excited potentials with ultrashort pulses and no frequency tuning.