Quantum correlation measurement of laser power noise below shot noise

In this article, the quantum correlation measurement technique as a method of power noise monitoring is investigated. Its principal idea correlating two photodetector signals introduced and contrasted to conventional approach, which uses only single photodetector. We discuss how scheme can be used obtain information below shot detected beam also electronic dark individual photodetectors, both not possible with approach. Furthermore, experimental results are presented, that demonstrate detection technical laser one order magnitude beam.