Coupled atomic coherences induced by a standing wave

Atomic coherence effects with a strong standing-wave coupling field on a four-level system of hot Rb atoms are investigated. Amplitude modulation and phase modulation of the strong standing-wave field are coherently coupled in linear and nonlinear atomic polarizations in various multi-wave mixing processes. Such coupled atomic coherence effect leads to one-photon triple-bandpass filters in an electromagnetically induced transparency structure and two-photon bandgaps at two different wavelengths under two-photon resonance in the hot four-level Rb atoms. Such system can be useful for dispersion compensation in multi-channel WDM systems, all-optical switching and optical filters at multiple wavelengths.