A. Settimi

Quasi-normal frequencies in open cavities: An application to photonic crystals

The electromagnetic field in an optical open cavity is analyzed in the framework of the Quasi-Normal Modes theory. The role of the complex quasi-normal frequencies in the transmission coefficient and their link with the density of quasi-modes function is clarified.An application to a quarter-wave symmetric one-dimensional photonic crystals is discussed to illustrate the usefulness and the meaning of our results.

Quantum counter-propagation in open optical cavities via the quasi-normal-mode approach

By using the quasi-normal-mode (QNM) formalism in a second quantization scheme, the problem of the counter-propagation of electromagnetic fields inside optical cavities is studied. The links between QNM operators and canonical destruction and creation operators describing the external free field, as well as the field correlation functions, are found and discussed. An application of the theory is performed for open cavities whose refractive index satisfies symmetric properties.

Quasi-normal modes description of waves in 1-D photonic crystal

For the first time the quasi normal mode treatment is used and extended to the description of the scalar field behaviour in one dimensional photonic crystals. A one-dimensional photonic crystal is a particular configuration of an open cavity, where discontinuities into refractive index give rise to field confinement. A discussion of the complex eigenvalues and eigenfrequencies, as well as the corresponding field distribution, is presented.

On the Divergenceless Property of the Magnetic Induction Field

Maxwells equations beautifully describe the electromagnetic fields properties. In what follows we will be interested in giving a new perspective to divergence-free Maxwell’s equations regarding the magnetic induction field: . To this end we will consider some physical aspects of a system consisting of massive nonrelativistic charged particles, as sources of an electromagnetic field (e.m.) propagating in free space. In particular the link between conservation of total momentum and divergence-free condition for the magnetic induction field will be deeply investigated. This study presents a new context in which the necessary condition for the divergence-free property of the magnetic induction field in the whole space, known as solenoidality condition, directly comes from the conservation of total momentum for the system, that is, sources and field. This work, in general, leads to results that leave some open questions on the existence, or at least the observability, of magnetic monopoles, theoretically plausible only under suitable symmetry assumptions as we will show.

Stimulated emission control in Photonic Crystals: Strong coupling regime in QNM approach

Stimulated emission, in strong coupling regime, in a one dimensional photonic crystals is described by considering two counter-propagating pumps. Quasi normal mode approach is used and coherent control of the Rabi splitting is discussed.

Density of modes for 2D finite photonic crystal structures

The density of modes for an open cavity constituted by a finite 2D photonic crystal is discussed. Modes depend on the cavity excitation and on the finite transverse and longitudinal confinement introduced by the finite sizes.