M. Bajcsy, S. Hofferberth, V. Balic, T. Peyronel, M. Hafezi, A. S. Zibrov, V. Vuletic, and M. D. Lukin,
Efficient All Optical Switching Using Slow Light Within a Hollow Fiber, Phys. Rev. Lett. 102, 203902 (2009).
Fig. 1. (a) Four-level system for nonlinear optical switching using ~1000 Rb atoms confined in a hollow-core optical fiber. (b) Timing sequences for probe, control, and switch fields. (d) Probe transmission through the fiber without (red) and with (blue) the switch field present. A few hundred switch photons are sufficient to change the probe transmission by 1/e.
We have demonstrated a fiber-optical switch that is activated at tiny energies corresponding to a few hundred optical photons per pulse. This is achieved by simultaneously confining both photons and a small laser-cooled ensemble of atoms inside the microscopic hollow core of a single-mode photonic-crystal fiber and using quantum optical techniques for generating slow light propagation and large nonlinear interaction between light beams. This work is a joint CUA experiment of Lukin’s Harvard and Vuletic’s MIT group.