Enhanced four-wave mixing by atomic coherence in a Pr3+:Y2SiO5 crystal.

We experimentally demonstrate an enhanced four-wave mixing (FWM) based on atomic coherence in a Pr3+:Y2SiO5 crystal. By employing coherent population return and fractional stimulated Raman adiabatic passage to prepare maximum atomic coherence in the crystal, an efficient FWM signal can be generated. By measuring the generated FWM signal, the time-dependent atomic coherence is monitored. Such an enhanced FWM in solids may have practical applications in nonlinear optics and laser spectroscopy. [ABSTRACT FROM AUTHOR]