An experimental investigation of a sonic underexpanded jet injected normally into a Mach 2.25 crossflow is reported. The jet exit geometry was circular and was operated at a jet-to-crossflow momentum flux ratio of 1.7. As a means of excitation to the flow field, an energy pulse from a Q-switched Nd:YAG laser was focused in the center of the jet exit, creating induced optical breakdown of air. The resulting flow field (as well as the unperturbed flow) was analyzed with schlieren photography and partcle image velocimetry. Analysis of phase averaged schlieren images suggested that the resulting blast wave from the laser pulse disrupted the structure of the barrel shock and Mach disk. The two-component velocity field data revealed that the excitation pulse also caused a perturbation to the jet shear layer which followed in the wake of the blast wave.