High-efficiency quantum-nondemolition single-photon-number-resolving detector

Abstract

We discuss an approach to the problem of creating a photon-number-resolving detector using the giant Kerr nonlinearities available in electromagnetically induced transparency. Our scheme can implement a photon-number quantum-nondemolition measurement with high efficiency $(\ensuremath{\sim}99%)$ using fewer than 1600 atoms embedded in a dielectric waveguide.