S. Severini

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.

Photonic bandgap structures in planar nonlinear waveguides: application to squeezed-light generation

Quadrature-amplitude and phase squeezing are theoretically investigated in a planar waveguide geometry where the use of a linear grating fabricated on top of the waveguide reproduces a photonic bandgap structure. The introduction of a nonlinear grating, obtained with a modulation of the nonlinear susceptibility χ(2), provides an additional degree of freedom that allows, together with the linear grating, tuning of the fundamental field in a selected resonance of the transmission spectrum and, at the same time, control of the phase-matching condition between the fundamental and second-harmonic fields. The results show that quadrature-amplitude squeezing is achieved for the fundamental field, increasing the second-harmonic input intensity. The second-harmonic field is tuned in the passband of the photonic bandgap. The low nonlinear conversion efficiency, given by a suitable selection of the mismatch, gives rise to the possibility of having a fundamental field of quite the same intensity, but less noisy than at the entry.

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.

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.

Photonic band gap structures in planar nonlinear waveguides: application to squeezing light generation

Quadrature-amplitude and phase squeezing are investigated in a nonlinear planar waveguide geometry under conditions for which the use of a linear grating fabricated on top of the waveguide reproduces a photonic band gap structures.

Non classical behaviours of optical field in Photonics band gaps structures

A theoretical analysis of the quantum behaviours of radiation field’s propagation in Photonic Band Gaps structures is performed. We use quantum scattering approach to obtain some interesting bounds for propagation coefficients.

Quantum properties of optical field in photonic band gap structures

A theoretical analysis of the quantum behaviour of radiation fields propagation in photonic band gaps structures is performed. In these initial calculations we consider linear inhomogeneous and nondispersive media.