Hexapole transport and focusing of vibrationally excited NO molecules prepared by optical pumping

We present a detailed report of experiments where hexapole focusing is combined with stimulated emission and Franck–Condon optical pumping techniques on a molecular beam. We show that this approach allows one to achieve a high degree of control over the molecule's ro-vibronic quantum numbers, its laboratory frame velocity, and its transverse divergence. Specifically, new ways of manipulating beams of vibrationally excited molecules emerge, including: (1) transverse refocusing and concomitant improved efficiency for transport of the vibrationally excited molecules, (2) relative enrichment of the concentration of the vibrationally excited molecules with respect to the unexcited portion of the beam, and (3) orientation of vibrationally excited molecules. Laser induced fluorescence, fluorescence depletion, Franck–Condon pumping, stimulated emission pumping, resonance enhanced multi-photon ionization, and hexapole focusing all provide spectroscopic probes into the detailed characteristics of this experiment.