261 research outputs found
Gap maps and intrinsic diffraction losses in one-dimensional photonic crystal slabs
A theoretical study of photonic bands for one-dimensional (1D) lattices
embedded in planar waveguides with strong refractive index contrast is
presented. The approach relies on expanding the electromagnetic field on the
basis of guided modes of an effective waveguide, and on treating the coupling
to radiative modes by perturbation theory. Photonic mode dispersion, gap maps,
and intrinsic diffraction losses of quasi-guided modes are calculated for the
case of self-standing membranes as well as for Silicon-on-Insulator structures.
Photonic band gaps in a waveguide are found to depend strongly on the core
thickness and on polarization, so that the gaps for transverse electric and
transverse magnetic modes most often do not overlap. Radiative losses of
quasi-guided modes above the light line depend in a nontrivial way on structure
parameters, mode index and wavevector. The results of this study may be useful
for the design of integrated 1D photonic structures with low radiative losses.Comment: 9 pages, 8 figures, submitted to Physical Review
Near-field interactions between a subwavelength tip and a small-volume photonic-crystal nanocavity
International audienceThe fundamentals of the near-field interaction between a subwavelength metallic tip and a photonic-crystal nanocavity are investigated experimentally and theoretically. It is shown experimentally that the cavity resonance is tuned without any degradation by the presence of the tip and that the reported near-field interaction is strongly related to the field distribution within the nanostructure. Then, in light of a perturbation theory, we show that this interaction is selectively related to the electric field or magnetic field distribution within the cavity, depending on the tip properties
Probing exciton localization in non-polar GaN/AlN Quantum Dots by single dot optical spectroscopy
We present an optical spectroscopy study of non-polar GaN/AlN quantum dots by
time-resolved photoluminescence and by microphotoluminescence. Isolated quantum
dots exhibit sharp emission lines, with linewidths in the 0.5-2 meV range due
to spectral diffusion. Such linewidths are narrow enough to probe the inelastic
coupling of acoustic phonons to confined carriers as a function of temperature.
This study indicates that the carriers are laterally localized on a scale that
is much smaller than the quantum dot size. This conclusion is further confirmed
by the analysis of the decay time of the luminescence
Les colloides : Jeu de billes à l'échelle Nanométrique ?
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SMART FORCE: the microfluidic tool to explore your colloidal solution (self-assembly, ultrasensitive analysis...)
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Lithographie par assemblage capillaire : le projet SMART FORCE
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SMART FORCE: the microfluidic tool to explore your colloidal solution (self-assembly, ultrasensitive analysis...)
International audienc
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