ABSTRACT
We will begin our journey through the background of quantum
optics with an elementary, but quantitative, classical theory of
radiative fields.Wewill first briefly outline the electromagnetic (EM)
theory of radiation, and describe how the EM radiation may be
understood as a wavewhich can be represented by a set of harmonic
oscillators. We shall describe how the free or non-interacting EM
field may be understood as a collection of harmonic oscillators
which is quantized in the standard manner, and whose energy
cannot be zero as a consequence of the basic non-commutability of
the canonical field variables. This chapter discusses the properties
of plane EM waves and normalization of the EM field in one
dimension. This is followed by a description of the Hamiltonian
and the amplitudes of the EM field in terms of the annihilation
and creation operators. Based on this chapter, it is possible to
considerably simplify the formulation of the physical basis for the
mathematical description of the major problems of quantum optics.