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Gardanne, France

Szeftel J.,Ecole Normale Superieure de Cachan | Sandeau L.,PixInBio SAS | Sandeau N.,Aix - Marseille University | Delezoide C.,Ecole Normale Superieure de Cachan | Khater A.,University of Maine, France
Optics Communications

The time growth of the electromagnetic field at the fundamental and double frequencies is studied from the very onset of the second harmonic generation (SHG) process for a set of dipoles lacking a symmetry centre and exhibiting a nonresonant coupling with a classical electromagnetic field. This approach consists first of solving the Schrödinger equation by applying a generalised Rabi rotation to the Hamiltonian describing the light-dipole interaction. This rotation has been devised for the resulting Hamiltonian to show up time-independent for both components of the electromagnetic field at the fundamental frequency and the second harmonic one. Then an energy conservation argument, derived from the Poynting theorem, is introduced to work out an additional relationship between the electromagnetic field and its associated electric polarisation. Finally this analysis yields the full time behaviour of all physical quantities of interest. The calculated results reproduce accurately both the observed spatial oscillations of the SHG intensity (Maker's fringes) and its power law dependence on the intensity of the incoming light at the fundamental frequency. © 2013 Elsevier B.V. Source

Belloni F.,PixInBio SAS | Sandeau L.,PixInBio SAS | Contie S.,PixInBio SAS | Vicaire F.,PixInBio SAS | And 2 more authors.
Progress in Biomedical Optics and Imaging - Proceedings of SPIE

We present a rigorous electromagnetic theory of the electromagnetic power emitted by a dipole located in the vicinity of a multilayer stack. We applied this formalism to a luminescent molecule attached to a CMOS photodiode surface and report light collection efficiency larger than 80% toward the CMOS silicon substrate. We applied this result to the development of a low-cost, simple, portable device based on CMOS photodiodes technology for the detection and quantification of biological targets through light detection, presenting high sensitivity, multiplex ability, and fast data processing. The key feature of our approach is to perform the analytical test directly on the CMOS sensor surface, improving dramatically the optical detection of the molecule emitted light into the high refractive index semiconductor CMOS material. Based on adequate surface chemistry modifications, probe spotting and micro-fluidics, we performed proof-of-concept bio-assays directed against typical immuno-markers (TNF-α and IFN-γ). We compared the developed CMOS chip with a commercial micro-plate reader and found similar intrinsic sensitivities in the pg/ml range. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE). Source

Sandeau L.,PixInBio SAS | Vuillaume C.,PixInBio SAS | Contie S.,PixInBio SAS | Grinenval E.,PixInBio SAS | And 5 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology

A novel CMOS bio-pixel array which integrates assay substrate and assay readout is demonstrated for multiplex and multireplicate detection of a triplicate of cytokines with single digit pg ml-1 sensitivities. Uniquely designed large area bio-pixels enable individual assays to be dedicated to and addressed by single pixels. A capability to simultaneously measure a large number of targets is provided by the 128 available pixels. Chemiluminescent assays are carried out directly on the pixel surface which also detects the emitted chemiluminescent photons, facilitating a highly compact sensor and reader format. The high sensitivity of the bio-pixel array is enabled by the high refractive index of silicon based pixels. This in turn generates a strong supercritical angle luminescence response significantly increasing the efficiency of the photon collection over conventional farfield modalities. © The Royal Society of Chemistry 2015. Source

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