title: Observation of coherent multiphoton processes in nuclear states.
abstract: We have used states of nuclear excitation to demonstrate coherent multiphoton processes that were the analogs of well-known effects occurring at optical frequencies. Success in exciting radio-frequency sidebands on hyperfine components of the 14.4-keV Mössbauer transition of (57)Fe is described. A distinctive feature of this experiment was that the absorbing foil was rigidly bound in a graphite sandwich intended to eliminate detrimental vibrations. A model is proposed that quantitatively explains these results in terms of coherently excited nuclear states and evidentially confirms the multiphoton nature of the sidebands observed in this experiment.
authors.forename: C B
authors.initials: CB
authors.lastname: Collins
authors.forename: B D
authors.initials: BD
authors.lastname: Depaola