title: Coherence switching in a four-level system: quantum switching
abstract: Dark resonance switching among three-laser interactions in a four-level system is observed by using an enhanced nondegenerate four-wave mixing technique. This coherence switching mechanism is based on simultaneous suppression and enhancement of two-photon absorption and has a novel application to high-speed optical switches.
authors.affiliation: Telecommunications Basic Research Laboratory, Electronics and Telecommunications Research Institute, Daejun, 305-350 Korea.
authors.initials: BS
authors.lastname: Ham
authors.initials: PR
authors.lastname: Hemmer