Nonlinear Optics of Free Atoms and Molecules

D.C. Hanna, Michael A. Yuratich, D. Cotter

Lorenzo M. Narducci

Christopher P. Search, Pierre Meystre

P. D. Drummond, Karen V. Kheruntsyan, Hao He

Summary form only given. Parametric solitons or simultaneous solitary waves (simultons), involving the optical /spl chi//sup (2)/ nonlinearity, have been the topic of much recent theoretical and experimental interest in nonlinear optics. We propose a novel mechanism by which a similar phenomenon may occur in nonlinear atomic optics, in which coherent molecule formation in a Bose-Einstein condensate takes the place of second harmonic generation. This requires a coupling that converts two atoms into one molecule, thus generating coupled atomic and molecular Bose-Einstein condensates. Our model includes a coherent molecular formation process (i.e., without dissipation) in an atomic BEC vapor, either through a Feshbach resonance or Raman photo-association. The coherently coupled atom-molecular condensate could provide a route to the observation of a localized three-dimensional BEC soliton, even in the absence of a trap potential. A possible application is in the free propagation of a non-diverging atom laser pulse, thus greatly increasing the intensity in an atom laser beam.

S. L. Rolston, William D. Phillips

Vyacheslav A. Trofimov

Physical reasons for the development of spatial and temporal instabilities realizing in optical bistability (OB) cavity- free systems are analyzed. It is shown that there are certain types of instability. We describe diffraction instability of light beams due to its propagation through a boundary on a high absorption domain. We consider instability generated by nonlinear dependence of a relaxation time of excited states of atoms (molecules) on vibration temperature or on room temperature under the condition of presence (or absence) of nonlinear absorption. We investigate instability due to an influence of laser- induced electric field and instability caused by the delay in a scheme with additional lateral feedback and instability in a scheme with mirror having a hole at its axis caused by dynamical lenses.