Using a lifetime broadened N-scheme with an active-Raman-gain (ARG) Lambda core, we show that large nonlinear phase shift can be induced without signal wave attenuation. The new scheme is not based on the ultra-slow-wave technique and it does not exhibit the signal wave attenuation or distortion associated with weakly-driven electromagnetically-induced-transparency-based schemes. We show that the signal wave acquires a large nonlinear phase shift and travels with superluminal propagation characteristics. This raises the possibility of rapidly responding nonlinear phase switching and phase gates for information science.
Citation: Physical Review A
Pub Type: Journals
gain medium, nonlinear optics, phase shifter