Micro-resonator based all-optical transistor
  We present theoretical estimates for a high-speed, low-loss, all-optical transistor using a micro-resonator device, whose fields interact evanescently with Rubidium vapor. We use a four-level electromagnetically induced absorption scheme to couple the light fields of the transistor. We show results indicating that a weak control beam can switch a much stronger signal beam, with contrast of greater than 25 dB and loss less than 0.5 dB. The switching timescale is on the order of 100 ps. 
B. D. Clader and S. M. Hendrickson
quant-ph physics.optics