Linear chirped pulses in a Raman excitation scheme provide selective excitation of only one target transition (single mode) in a molecule without disturbing any other transitions or molecules. Selectivity is guaranteed by the adiabaticity of the pulse excitation, which allows manipulation by only a resonant mode while leaving all of the other modes unperturbed. This in turn allows for enhanced imaging or spectroscopic analysis of a sample that contains one or more of the molecules.