An Introduction to Quantum Optics

9Quantum Theory of Optical Coherence

In this chapter, we study the quantum theory of optical coherence, which has been especially successful in dealing with the coherent phenomena of light at the quantum level. In fact, we have inexplicitly introduced the quantum concepts into the simple model of radiation from the very beginning of Chapter 1, although no quantization is involved. The large number of sub-sources, either radiate independently or coherently, are connected with a large number of atomic transitions. The very basic contribution to the radiation field from each sub-source is therefore the creation of a photon. In the classical bright light condition, a measurement may involve the creation and annihilation of a large number of photons. ...