Efficient all-optical routing using dynamically induced transparency windows and photonic band gaps

By investigating the steady optical response of a cold atomic ensemble, we find that one high-reflection band gap and one high-transmission region with comparable widths may be dynamically induced and well controlled around the probe resonance by a traveling-wave coupling field and a standing-wave grating field. The high-reflection band gap and the high-transmission region are then applied to devise a scheme for all-optical routing of two different light signals toward either the opposite or the same directions. This all-optical routing scheme is very efficient because both reflected and transmitted signals experience little loss and deformation, and thus it may have important applications in quantum information networks. ©2010 The American Physical Society