Gaël David Osowiecki

Vertically coupled plasmonic slot waveguide cavity for localized biosensing applications

We propose and study an integrated refractive index sensor which is based on a plasmonic slot waveguide cavity. In this device, a guided mode supported by a silicon photonic wire waveguide is vertically coupled to a metal-dielectric-metal cavity separated by a silicon oxide spacer. We perform an in-depth study that links the geometrical parameters of the sensor to the coupling mechanism and sensitivity of the plasmonic slot waveguide cavity. Simulation results promise that local changes of refractive index can be measured with a high sensitivity of around 600 nm/RIU in a femto-liter volume. These results are obtained with three-dimensional time and frequency domain simulations. Thanks to the high field enhancement in the slot of the plasmonic cavity, a high local sensitivity to changes of refractive index is obtained. Moreover, the high level of achieved decoupling between the bulk and the local sensitivity complies well with the requirements of biomolecular sensing.

Light confinement effect of nonspherical nanoscale solid immersion lenses

Abstract. We report on the light confinement effect observed in nonideally shaped (i.e., nonspherical) nanoscale solid immersion lenses (SIL). To investigate this effect, nanostructures of various shapes are fabricated by electron-beam lithography. When completely melted in reflow, these noncircular pillars become spherical, while incomplete melting results in nonspherically shaped SILs. Optical characterization shows that nonideal SILs exhibit a spot size reduction comparable with that of spherical SILs. When the size of the SIL is of wavelength scale or smaller, aberrations are negligible due to the short optical path length. This insensitivity to minor variations in the shape implies a large tolerance in nano-SIL fabrication.

Investigation of the Propagation Length of Bloch Surface Waves on One Dimensional Photonic Crystals, 2018 International Conference on Optical MEMS and Nanophotonics (OMN)

A 1D photonic crystal structure sustaining optical surface waves is investigated. The propagation length of the surface mode is studied both using an eigenmode model and a rigorous time domain solver. The two models show good convergence. Our results demonstrate that by a carefully designed 1D photonic crystal, dielectric surface waves may propagate over several millimeters, even if a Kretschmann-type coupling configuration is used.

Bloch Surface Waves Fabry- Pérot Nanocavity

We demonstrate the first cavity confinement of Bloch surface waves in the fundamental mode of a Fabry–Perot cavity. The cavity consists of two distributed Bragg mirrors separated by a spacer of dimensions smaller than the wavelength (633nm). The cavity mode exhibits quality factor of 400. This quality factor is the highest recorded thus far for a subwavelength optical surface waves cavity.

Standing wave integrated Fourier transform spectrometer for imaging spectrometry in the near infrared

We show the miniaturization and parallelization of a scanning standing wave spectrometer with a long term goal of creating a compact imaging spectrometer. In our standing wave integrated Fourier transform spectrometer, light is injected with micro-lenses into several optical polymer waveguides. A piezo actuated mirror located at the waveguide end-facet can shift the interferogram to increase its sampling frequency. The spatial distribution of the standing wave intensity inside the waveguide is partially scattered out of the plane by a periodic metallic grating and recorded by a CCD camera. We present spectra acquisition for six adjacent waveguides simultaneously at a wavelength of 632.8 nm.

Localized biomolecular sensing enabled through plasmonic nanocavities

We propose and study an integrated refractive index sensor which is based on a plasmonic slot cavity integrated on silicon-on-insulator wafers. In this device, the guided mode is vertically coupled to the cavity which is a metal-dielectricmetal waveguide and is separated from a photonic wire waveguide by a silicon dioxide spacer. We perform an in-depth study that links the geometrical parameters to the coupling and sensitivity. The strong coupling from the dielectric waveguide to the plasmonic slot waveguide cavity allows a local change in refractive index to be detectable with a high sensitivity of around 600 nm/RIU in a femto-liter volume. These results are obtained with three-dimensional time domain simulations made with the CST Microwave Studio. The sensing performance of the devices are presented and compared to the practical needs to achieve localized biomolecular sensing.

Light-trapping in the near field: the case for plasmonic thin-film solar cells

We study the plasmonic and the non-plasmonic regimes of operation of a thin-film amorphous-silicon solar cell. By rigorous calculation, we discuss the impact of the cell geometry on the nature of its optical resonances.

Publisher’s note: Light confinement effect of nonspherical nanoscale solid immersion lenses

This paper [J. Micro/Nanolith. MEMS MOEMS. 12, (2 ), 023015 (Apr–Jun 2013)] was mistakenly published as a regularly contributed paper in the April–June 2013 issue of JM3. It was intended to be published with the special section on “Advanced Fabrication of MEMS and Photonic Devices” guest edited by Freymann, Maher, and Suleski in the October-December 2013 issue of JM3. The paper can be found online at CrossRef[[XSLOpenURL/10.1117/1.JMM.12.2.023015]]. It also appears in the October–December 2013 print issue with the special section.