Biomedical subjects

N Mattiucci

Publications and source records attributed to N Mattiucci.

4 recordsLinked to original sources

PubMed2005

TE and TM guided modes in an air waveguide with negative-index-material cladding.

We numerically demonstrate that a planar waveguide in which the inner layer is a gas with refractive index n0 = 1, sandwiched between two identical semi-infinite layers of a negative index material, can support both transverse electric and transverse magnetic guided modes with low losses. Recent developments in the design of metamaterials with an effective negative index suggest that this waveguide could operate in the infrared region of the spectrum.

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PubMed2004

Density of modes and tunneling times in finite one-dimensional photonic crystals: a comprehensive analysis.

We present a unified treatment of density of modes and tunneling times in finite, one-dimensional photonic crystals. We exploit connections and differences between the various approaches used to calculate the density of modes, which include the Green function, the Wigner phase time, and the electromagnetic energy density, and conclude that the Green function is always the correct path to the true density of modes. We also find that for an arbitrary structure the density of modes can always be found as the ratio between the power emitted by a source located inside the structure and the power emitted by the same source in free space, regardless of absorption or dispersion.

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PubMed2003

Quasinormal-mode description of waves in one-dimensional photonic crystals.

Quasinormal-mode treatment is extended to the description of scalar field behavior in one-dimensional photonic crystals. A one-dimensional photonic crystal is a particular configuration of an open cavity, where discontinuities of the refractive index give rise to field confinement. This paper presents, for a one-dimensional photonic crystal, a discussion about the completeness of the quasinormal-mode representation and, moreover, a discussion on the complex eigenfrequencies, as well as the corresponding field distribution. The concept of density of modes is also discussed in terms of quasinormal modes.

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PubMed2003

Dynamics of counterpropagating pulses in photonic crystals: enhancement and suppression of stimulated emission processes.

Using numerical methods, we study the propagation of counterpropagating pulses in finite photonic crystals. We show that linear interference and localization effects combine to either enhance or suppress stimulated emission processes, depending on the initial phase difference between the input pulses. We consider the example of second harmonic generation, where we find a maximum contrast of three orders of magnitude in nonlinear conversion efficiency as a function of the input phase difference between incident pulses. We interpret these results by viewing the photonic crystal as an open cavity, with a field-dependent, electromagnetic density of modes sensitive to initial and boundary conditions.

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