D. Peyrade

Ultra-High Q/V Fabry-Perot microcavity on SOI substrate

We experimentally demonstrate an ultra high Q/V nanocavity on SOI substrate. The design is based on modal adaptation within the cavity and allows to measure a quality factor of 58.000 for a modal volume of 0.6(lambda/n)(3) . This record Q/V value of 10(5) achieved for a structure standing on a physical substrate, rather than on membrane, is in very good agreement with theoretical predictions also shown. Based on these experimental results, we show that further refinements of the cavity design could lead to Q/V ratios close to 10(6).

All-optical switching in 2D silicon photonic crystals with low loss waveguides and optical cavities

A study of the optical transmission of low-loss W1.5 photonic crystal waveguides built on silicon membranes and operating at telecom wavelengths is presented. The feasibility of performing all-optical switching is demonstrated for W1.5 waveguides coupled with L3 cavities, systems amenable for incorporation in on-chip devices. Switching of waveguide transmission is achieved by means of optical excitation of free carriers using a 2.5 ns pump laser. Experimental results are reproduced by finite-difference time-domain simulations which model the response of the finite system and band structure calculations describing the infinite, ideal one.

Ultra-high-reflectivity photonic-bandgap mirrors in a ridge SOI waveguide

Microcavities consisting of two identical tapered mirrors etched into silicon-on-insulator ridge waveguides are investigated for operation at telecommunication wavelengths. They offer very small modal volumes of approximately 0.6 (λ/n)3 and calculated intrinsic Q factors of 400 000. We have measured a Q factor of 8900 for a loaded cavity, in agreement with the theoretical value. In contrast to recent works performed on suspended membranes, the buried SiO2 layer is not removed. The cavities possess strong mechanical robustness, thus making them attractive from the viewpoint of integration in large systems. The cavity Q factor is much larger than those previously obtained for similar geometries on a substrate.

Determination of Clausius–Mossotti factors and surface capacitances for colloidal particles

We propose a method to experimentally determine the Clausius–Mossotti factors and surface capacitances of colloidal particles. This two-step method is based on the following: (i) a precise positioning of particles on activated electrodes according to the applied frequency of an electric field and (ii) particles velocities measurements from a pure dielectrophoretic regime to build the Clausius–Mossotti factor. It confirms previous literature methods and measures the surface capacitance values for a wide range of particles such as polystyrene, silica, and gold whose diameters are at least 200 nm.

Probing exciton localization in nonpolar Ga N ∕ Al N quantum dots by single-dot optical spectroscopy

We present an optical spectroscopy study of nonpolar

Separation of colloidal nanoparticles using capillary immersion forces

\mathrm{Ga}\mathrm{N}∕\mathrm{Al}\mathrm{N}

Ultracompact silicon-on-insulator ridge-waveguide mirrors with high reflectance

quantum dots by time-resolved photoluminescence and by microphotoluminescence. Isolated quantum dots exhibit sharp emission lines, with linewidths in the

Assembly of microparticles by optical trapping with a photonic crystal nanocavity

0.5\char21{}2\phantom{\rule{0.3em}{0ex}}\mathrm{meV}

Short Bragg mirrors with adiabatic modal conversion

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.

Assisted convective-capillary force assembly of gold colloids in a microfluidic cell: Plasmonic properties of deterministic nanostructures

Capillary force assembly (CFA) of colloidal particles usually results in closed-packed films or particle aggregation within topographic features. In this work, it is shown that CFA can also be exploited to both localize and separate nanoparticles (d=50–200nm) when template shape and wettability are controlled. Well-defined geometric arrangements of one to four closely spaced particles (30–50nm separation) were realized in large arrays using this technique to demonstrate that particle aggregation during dewetting can be eliminated. Ordered SiO2 nanopillars in tight groupings were obtained by combining low-resolution e-beam lithography (>100nm) with CFA and etching. This approach provides a simple route to fast and precise placement of nanostructures using relatively low-resolution pattern making techniques.