Experimental realization of a semiconductor photon number amplifier and a quantum optical tap

Two configurations involving high quantum efficiency photodetectors and light emitting diodes have been investigated. A light beam was detected with a photodetector and its photocurrent was used to measure the incoming beam. Simultaneously, the photocurrent was used, with and without amplification, to regenerate the absorbed beam. With these schemes photon number amplification, duplication, and information tapping without introducing any significant noise to the downstream propagating beam could be experimentally realized.