GENERATION OF SUPERLUMINAL IMAGES WITH FOUR-WAVE-MIXING IN ATOMIC VAPOR
We demonstrate superluminal pulse generation via noncollinear four-wave mixing in hot rubidium vapor with a double-Λ scheme. Two steep gain features result in a large dispersion near the gain lines, resulting in both slow and fast light effects. One novel feature of this system is that the generated conjugate pulse can also be superluminal, and that the group velocity of both the probe and the conjugate can be tuned over a wide range via the probe’s two-photon detuning and
also via the probe power. We also can imprint spatial patterns on the probe pulse and send it through the fast-light medium. Thereby we show that anomalous dispersion can be used as an additional degree of freedom for image processing, complementary to existing schemes to slow down and store images. Our scheme allows us to investigate the propagation of spatial information through a medium of anomalous dispersion.