Abstract

The photon model of the quantum electromagnetic(EM) field has recently been developed further for the areas of Cavity QED and Quantum Optics in Dielectric Media. In microscopic theories [1] for the media, EM field quantization is the same as in free space, so the photon model applies. However, if the classical optical device, material media is treated macroscopically (such as via a spatially dependent permittivity) the validity of the photon model is not obvious. Nevertheless, canonical quantization of the EM field via expanding the vector potential in terms of the true (normal) modes for the system - as determined from a Helmholtz equation, does show that the EM field is again equivalent to independent quantum harmonic oscillators (QHO), one for each true (non free space) mode [2,3,4]. Moreover, if idealised or quasi modes are used instead - as obtained from an idealised optical system permittivity, once again QHO are obtained, one for each quasi mode [2,5]. However, the QHO are now coupled - photon exchange processes between quasi modes occur. Extensions of the quasi mode theory have been made to cases where two sets of quasi modes are needed [6]. It has also been applied to understanding simple optical systems and phenomena such as the beam splitter [7], reflection and refraction [6] and to justifying the standard model used in Cavity QED [8].

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