Stimulated Generation of Superluminal Light Pulses via Four-Wave Mixing

Abstract

We report on the four-wave mixing of superluminal pulses, in which both the injected and generated pulses involved in the process propagate with negative group velocities. Generated pulses with negative group velocities of up to v(g)=-1/880c are demonstrated, corresponding to the generated pulse's peak exiting the 1.7 cm long medium ≈50 ns earlier than if it had propagated at the speed of light in vacuum, c. We also show that in some cases the seeded pulse may propagate with a group velocity larger than c, and that the generated conjugate pulse peak may exit the medium even earlier than the amplified seed pulse peak. We can control the group velocities of the two pulses by changing the seed detuning and the input seed power.

Fast light and quantum correlations from four-wave-mixing in atomic vapor

“…1,7,9,10,12 The system has also been shown to allow for strong relative intensity squeezing of bright twin beams and for two-mode squeezed vacuum (witnessed via balanced double-homodyning 13 ). While slow-and fastlight effects typically deteriorate the correlations between the twin-beams, significant delays have nevertheless been shown, where the correlations between the beams are still in the quantum regime.…”

“…(Adopted from. 7 ) modulator, which detunes the probe relative to the pump by the 3 GHz ground state splitting and an additional two-photon detuning δ.…”

Quantum mutual information of an entangled state propagating through slow- and fast-light media

“…The bipartite continuous-variable entangled state is generated via a four-wave mixing (4WM) process in hot rubidium vapor. 14,15 One of the two modes is then sent through a fast (or slow) light medium, after which we characterize the entanglement and quantum mutual information of the resulting state. 16,17 We find that when propagating through a region of normal dispersion (slow light), the peak of the quantum mutual information shared between the modes may be delayed beyond the envelope of the reference mutual information curve.…”

Bipartite quantum correlations in a fast-light medium generated with four-wave-mixing in rubidium vapour

“…The four-wave mixing process allows both the generation of a large negative group index near its gain-line features [1][2][3] and the generation of strongly correlated twin-beams [4]. Here we create a pair of twin beams with -2.5 dB intensity difference squeezing and send one of the beams through a second four-wave mixing process, which acts as a fast light medium.…”