Generation, Detection, and Application of High-Intensity Photon-Number-Eigenstate Fields

Near-photon-number-eigenstate fields lead to dramatic signal-to-noise improvement beyond the standard shot-noise limit in many optical systems, including interferometric gravitational-wave detectors. These fields may be generated from parametric processes with measurement feedback. Degradation from nonideal photodetection can be overcome by appropriate optical preamplification. It is estimated that an order-of-magnitude improvement can already be obtained with existing devices.