Laser Optics '98: Nonlinear and Coherent Optics

Yiran Yin, An‐Ning Xu, Bei Liu +1 more

We compare the nonlinear magneto-optical rotation (NMOR) effect in a single-beam probe scheme and a two-beam Raman-coherence-assisted scheme using cold rubidium atoms produced with an integrating sphere apparatus. In both schemes, NMOR arising from D1 and D2 excitation combinations was studied. We show that adding a Raman-coherence manipulation laser can substantially increase the NMOR, and the largest NMOR enhancement occurs when both probe and Raman-coherence lasers couple the same D2 transitions with different detunings. For far-off resonance excitation with a weak probe laser, we show that the Raman-coherence-assisted NMOR enhancement can be about 6 times larger than the single probe scheme operated under the same conditions. The Raman-coherence-enhanced NMOR is also shown to be substantially larger than that from an optically pumped magnetometer using a single strong circularly polarized probe.

Michael S. Feld, Vladilen S Letokhov

Vladilen S Letokhov, Michael S. Feld

Jani Oksanen, Jukka Tulkki

Coherent nonlinear feedback is shown to eliminate the most critical transient problems in the known active integrated all-optical flip-flop structures, potentially increasing the operating speed by an order of magnitude. The nonlinearity is based on the interference of two coherent optical fields and on operating the pertinent laser amplifiers only above the laser threshold. Therefore the lasers have an approximately constant carrier density and an ever present photon population in the laser mode. This enables fast switching. Numerical analysis based on coupled rate equations demonstrates switching times below 25ps (40GHz).

P. Ewart

Vladimir A. Sautenkov, Sergey A. Saakyan, E V Vilshanskaya +3 more

We have investigated the nonlinear selective reflection of a laser beam (λ = 780 nm) from a high density rubidium vapor. The laser frequency was tuned over atomic transitions and coherent optical excitation of the atomic vapor was realized. The observed narrowing of reflection spectral profile is associated with a competition of two nonlinear processes: optical field induced coherent broadening (Rabi broadening) and optical saturation induced decreasing of dipole–dipole broadening of atomic transitions. For more complete understanding the spectral narrowing we suggest to perform a set of new experiments.