Biomedical subjects

Carole Deumié

Publications and source records attributed to Carole Deumié.

7 recordsLinked to original sources

PubMed2006

Optical characterization of an unknown single layer: Institut Fresnel contribution to the Optical Interference Coatings 2004 Topical Meeting Measurement Problem.

We present the characterizations performed at the Institut Fresnel for the Measurement Problem of the Optical Interference Coatings 2004 Topical Meeting. A single layer coated on a fused-silica substrate of unknown composition and parameters is analyzed in terms of optogeometrical parameters, uniformity, and scattering. We determine the refractive index and the average thickness of the coating, then provide the localized determination of the thickness with a 2 mm spatial resolution. Topography measurements include atomic force microscopy and angle-resolved scattering measurements. These results are completed thanks to a Taylor Hobson noncontact 3D surface profiler.

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PubMed2006

Light-scattering characterization of transparent substrates.

Angle-resolved light scattering has been used for decades to quantify the surface roughness of optical components. However, because this technique is affected by the contribution of both interfaces of the sample, it cannot be applied to transparent substrates. We show how to overcome this issue and apply these principles to the characterization of superpolished samples.

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PubMed2006

Multidielectric quarter-wave coatings on microspheres: a study in colorimetric space.

Spectral properties of quarter-wave stacks deposited on microspheres are investigated with Mie theory. These properties are converted into colorimetric spaces to deal with visual applications. An ion-beam-sputtering process is then implemented to produce elementary stacks on the spheres, and the resulting powders are characterized.

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PubMed2006

Ellipsometry of reflected and scattered fields for the analysis of substrate optical quality.

Specular ellipsometry is a well-known and efficient technique to characterize surfaces and coatings. This technique has been extended to the measurement of scattered light. We present an experimental setup, using a polarization modulator, which permits us to characterize transition layers and roughness without a calibration procedure. Experimental results are presented concerning transition layers for damage threshold applications and for rough surfaces or bulks.

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PubMed2004

Determination of refractive indices of opaque rough surfaces.

The refractive indices of optical materials are usually determined from spectrophotometric and ellipsometric measurements of specular beams. When the roughness of the interfaces increases, the energy in the specularly reflected and transmitted beams decreases and scattering becomes predominant. For strong roughness (compared to the incident wavelength) a surface does not exhibit specular reflection or transmission, making difficult the determination of the refractive index. We describe two techniques, based on scattering measurements, that one can use to determine the refractive indices of opaque inhomogeneous media.

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PubMed2002

Overcoated microspheres for specific optical powders.

We produce overcoated microspheres and try to obtain artificial optical powders with specific spectral properties. Electron-beam deposition is used with a particular vibration system. Calibration and characterization results are presented that validate the techniques and procedures for single-layers and quarter-wave mirrors.

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PubMed2002

Angle-resolved ellipsometry of light scattering: discrimination of surface and bulk effects in substrates and optical coatings.

Angle-resolved ellipsometry of light scattering is an original technique developed at the Fresnel Institute to identify scattering processes in substrates and multilayers. We extend the investigation because numerous experimental results proved that the technique can be of major interest for analysis of microcomponents and their scattering origins. Surface and bulk effects can be separated in most situations, as well as the oblique growth of materials and the presence of first-order contaminants.

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