Miniature Optical Particle Counter and Analyzer Involving a Fluidic-Optronic CMOS Chip Coupled with a Millimeter-Sized Glass Optical System.

Our latest advances in the field of miniaturized optical PM sensors are presented. This sensor combines a hybrid fluidic-optronic CMOS (holed retina) that is able to record a specific irradiance pattern scattered by an illuminated particle (scattering signature), while enabling the circulation of particles toward the sensing area. The holed retina is optically coupled with a monolithic, millimeter-sized, refracto-reflective optical system. The latter notably performs an optical pre-processing of signatures, with a very wide field of view of scattering angles. This improves the sensitivity of the sensors, and simplifies image processing. We report the precise design methodology for such a sensor, as well as its fabrication and characterization using calibrated polystyrene beads. Finally, we discuss its ability to characterize particles and its potential for further miniaturization and integration.

Design, fabrication and characterization of an AWG at 4.5 µm.

In this paper, we present the design, the fabrication and the characterization of an Arrayed Waveguide Grating (AWG) based on a SiGe graded index waveguide platform, operating at 4.5 µm. These devices were specifically designed to work together with an array of Distributed Feedback Bragg Quantum Cascade Lasers (DFB-QCL) emitting at different wavelengths. The AWG enables to combine the different light sources into a single output and the design adopted allows to maximize transmission over the entire spectral range defined by the array of DFB-QCLs.

Mlines characterization of the refractive index profile of SiGe gradient waveguides at 2.15 µm.

SiGe alloys present a large Infra-Red transparency window and a full compatibility with the standard Complementary Metal Oxide Semiconductor processing making them suitable for applications in integrated optics. In this paper we report on Mlines characterization of Si(1-x)Ge(x) graded index waveguides at 2.15 µm. First, a law giving the refractive index of a Si(1-x)Ge(x) alloy as a function of the Ge content x: n = 1.342x(2) + 0.295x + 3.451, has been experimentally established in the 0 < x < 0.4 range. Then, we have demonstrated that our methodology based on Mlines measurements can be used as short-loop non-destructive technique to provide feedback for sample growth.

Determination of surface-bound-fluorophore orientation by goniometric fluorescence polarization: application to quantification of DNA-chip readouts.

We present a polarized goniofluorimeter designed to measure the observation-angle and polarization-dependent intensity emitted by a group of surface-bound fluorescent molecules. We studied two types of surface bonding: In one case, dyes were adsorbed into the surface by spin coating, and in the other, dyes were covalently immobilized to DNA strands. Fluorescent dyes consisted of Cy3 and Alexa546. The substrate was a silicon wafer bearing a silicon dioxide layer. The different samples presented a wide panel of reproducible experimental behavior. By confronting experimental behavior with theory and simulation, we can explain these differences as directly linked to the mean orientation of fluorophores with respect to the surface.