Figure 1

(a) Schematic of the experimental setup. The counterpropagating pump beam is aligned at an angle of 10° with respect to the atom guide. The weak probe beam is aligned along the atom guide and shares the same polarization as the counterpropagating pump beam. In addition to these, a pair of transverse beams (not shown) in ${\sigma }^{+}-{\sigma }^{-}$ configuration are used to trap and cool atoms in the 2D MOT. (b) Absorption spectrum of the weak probe beam in the vicinity of the recoil induced resonance for small (solid line, $\mathrm{OD}=10$) and large (dashed line, $\mathrm{OD}=45$) optical depths. Inset: an absorption spectrum over a wider range of detunings reveals the Mollow absorption and gain features which are much broader than the RIR.Reuse & Permissions

Figure 2

Lensing due to the recoil induced resonance. (a) An image of the probe beam in the absence of atoms. (b) An image of a red-detuned probe beam after propagation through the ultracold medium. In this case, the ultracold medium amplifies the probe and also acts as a convex lens. (c) The image of the probe when detuned to the blue of the RIR. The ultracold medium absorbs the probe and acts as a concave lens.Reuse & Permissions

Figure 3

(a) Experimental setup for guiding the probe beam through the ultracold medium. (b) Images of the emergent probe beam for different input angles. (c) Corresponding images of the emergent probe in the absence of atoms. It can be seen that the fraction of light that is coupled into the waveguide can be increased by changing the input angle.Reuse & Permissions

Figure 4

Evidence of an enhanced path length due to optical waveguiding of the probe pulse. The bottom trace shows the probe pulse in the absence of the atoms. The middle trace [labeled (a)] shows a pulse with a bimodal structure. This corresponds to the image of the emergent probe showing both a guided fraction and a lensed fraction. The dotted lines show a least squares fit of this pulse to a sum of two Gaussian pulses with group delays ${\delta }_1$ and ${\delta }_2$ with ${\delta }_2\gg {\delta }_1$. The top trace [labeled (b)] shows the output when the lensed fraction is blocked by means of an iris. It can be seen that the output pulse corresponds to a single pulse with a delay of ${\delta }_2$. Here, ${\delta }_1=0.8\mu \mathrm{s}$ and ${\delta }_2=5.9\mu \mathrm{s}$. The traces are offset for clarity.Reuse & Permissions