Photons and Continuum States of Atoms and Molecules

Wolfgang Demtröder

N. K. Rahman, Carla Guidotti, M. Allegrini

Amichay Vardi, M. Shapiro, Klaas Bergmann

We demonstrate the feasibility of a laser induced complete population transfer to and from a continuum of states. We study the two-photon dissociation of v = 28; J = 1,...,10 sodium dimers. We demonstrate that using just a pair of "counter intuitively" ordered pulses we can dissociate 100% of the molecules in an ensemble. The scheme is shown to be stable with respect to the initial choice of rotational level and to fluctuations in the laser frequency and intensity. We also study the reverse phenomenon of complete population transfer from the continuum. We perform calculations on the radiative association of Na atoms to form the Na2 molecule in specific vib-rotational states. It is shown that two pulses of 20 nsec duration and as little as 6 MW/cm 2 peak power can photo-associate more than 98% of the atoms within a (pulse and velocity determined) relative effective distance, to yield Na2 molecules in the chosen v = 28; J = 10 vib-rotational state. This means that given a density of 10 16 atoms/cm 3 and a temperature of 7K, a 10Hz pulsed laser source of the above parameters can con- vert half of all the Na atoms in the ensemble to v = 28; J = 10 Na2 molecules within 15 seconds of operation.

Michèle Leduc, Nicolas Treps

Stefano Longhi

Classical wave optical analogs of coherent population transfer via a continuum, recently demonstrated for laser-driven atoms and molecules in the atomic physics context, are theoretically proposed for light waves propagating in waveguide-based photonic structures. In particular, it is shown that exploitation of the optical analogs of two-photon Rabi oscillations and stimulated Raman adiabatic passage via continuous states enables efficient transfer of light waves between two channel optical waveguides side coupled to a slab waveguide.

Claude N. Cohen-Tannoudji, J. Dupont-Roc, G. Grynberg