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Peynier, France

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Daoudi K.,University of Twente | Van Den Berg P.J.,University of Twente | Rabot O.,Quantel Laser Diode | Kohl A.,Quantel Laser Diode | And 3 more authors.
Optics Express | Year: 2014

Ultrasound and photoacoustics can be utilized as complementary imaging techniques to improve clinical diagnoses. Photoacoustics provides optical contrast and functional information while ultrasound provides structural and anatomical information. As of yet, photoacoustic imaging uses large and expensive systems, which limits their clinical application and makes the combination costly and impracticable. In this work we present and evaluate a compact and ergonomically designed handheld probe, connected to a portable ultrasound system for inexpensive, real-time dualmodality ultrasound/photoacoustic imaging. The probe integrates an ultrasound transducer array and a highly efficient diode stack laser emitting 130 ns pulses at 805 nm wavelength and a pulse energy of 0.56 mJ, with a high pulse repetition frequency of up to 10 kHz. The diodes are driven by a customized laser driver, which can be triggered externally with a high temporal stability necessary to synchronize the ultrasound detection and laser pulsing. The emitted beam is collimated with cylindrical micro-lenses and shaped using a diffractive optical element, delivering a homogenized rectangular light intensity distribution. The system performance was tested in vitro and in vivo by imaging a human finger joint. © 2014 Optical Society of America.


Daoudi K.,University of Twente | Van Den Berg P.J.,University of Twente | Rabot O.,Quantel Laser Diode | Kohl A.,Quantel Laser Diode | And 3 more authors.
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2013

Photoacoustics is a hybrid imaging modality that is based on the detection of acoustic waves generated by absorption of pulsed light by tissue chromophors. In current research, this technique uses large and costly photoacoustic systems with a low frame rate imaging. To open the door for widespread clinical use, a compact, cost effective and fast system is required. In this paper we report on the development of a small compact handset pulsed laser probe which will be connected to a portable ultrasound system for real-time photoacoustic imaging and ultrasound imaging. The probe integrates diode lasers driven by an electrical driver developed for very short high power pulses. It uses specifically developed highly efficient diode stacks with high frequency repetition rate up to 10 kHz, emitting at 800nm wavelength. The emitted beam is collimated and shaped with compact micro optics beam shaping system delivering a homogenized rectangular laser beam intensity distribution. The laser block is integrated with an ultrasound transducer in an ergonomically designed handset probe. This handset is a building block enabling for a low cost high frame rate photoacoustic and ultrasound imaging system. The probe was used with a modified ultrasound scanner and was tested by imaging a tissue mimicking phantom. © 2013 Copyright SPIE.


Vial B.,École Centrale Marseille | Commandre M.,École Centrale Marseille | Zolla F.,École Centrale Marseille | Nicolet A.,École Centrale Marseille | Tisserand S.,Silios Technologies
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

Our approach consists in finding the eigenmodes and the complex eigenfrequencies of structures using a finite element method (FEM), that allows us to study mono- or bi-periodic gratings with a maximum versatility : complex shaped patterns, with anisotropic and graded index material, under oblique incidence and arbitrary polarization. In order to validate our method, we illustrate an example of a four layer dielectric slab, and compare the results with a specific method that we have called tetrachotomy, which gives us numerically the poles of the reflection coefficient (which corresponds to the eigenfrequencies of the structure). To illustrate our method, we show the eigenvalues of one- and two-dimensional gratings. © 2011 SPIE.


Caillat A.,Aix - Marseille University | Pascal S.,Aix - Marseille University | Tisserand S.,SILIOS Technologies | Dohlen K.,Aix - Marseille University | And 3 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

A GRISM, made of a grating on a prism, allow combining image and spectroscopy of the same field of view with the same optical system and detector, thus simplify instrument concept. New GRISM designs impose technical specifications difficult to reach with classical grating manufacturing processes: large useful aperture (>100mm), low groove frequency (<30g/mm), small blaze angle (<3°) and, last but not least, line curvature allowing wavefront corrections. In addition, gratings are commonly made of resin which may not be suitable to withstand the extreme space environment. Therefore, in the frame of a R&D project financed by the CNES, SILIOS Technologies developed a new resin-free grating manufacturing process and realized a first 80mm diameter prototype optically tested at LAM. We present detailed specifications of this resin-free grating, the manufacturing process, optical setups and models for optical performance verification and very encouraging results obtained on the first 80mm diameter grating prototype: >80% transmitted efficiency, <30nm RMS wavefront error, groove shape and roughness very close to theory and uniform over the useful aperture. © 2014 SPIE.


Vial B.,Aix - Marseille University | Commandre M.,Aix - Marseille University | Demesy G.,Aix - Marseille University | Nicolet A.,Aix - Marseille University | And 5 more authors.
Optics Letters | Year: 2014

The diffractive behavior of arrays of square coaxial apertures in a gold layer is studied. These structures exhibit a resonant transmission enhancement that is used to design tunable bandpass filters for multispectral imaging in the 7-13 μm wavelength range. A modal analysis is used for this design and the study of their spectral features. Thus we show that the resonance peak is due to the excitation of leaky modes of the open photonic structure. Fourier transform infrared (FTIR) spectrophotometry transmission measurements of samples deposited on Si substrate show good agreement with numerical results and demonstrate angular tolerance of up to 30 degrees of the fabricated filters. © 2014 Optical Society of America.


Vial B.,Aix - Marseille University | Demesy G.,Aix - Marseille University | Zolla F.,Aix - Marseille University | Nicolet A.,Aix - Marseille University | And 6 more authors.
Journal of the Optical Society of America B: Optical Physics | Year: 2014

We present a modal analysis of metal-insulator-metal (MIM)-based metamaterials in the far infrared region. These structures can be used as resonant reflection bandcut spectral filters that are independent of the polarization and direction of incidence. We show that this resonant reflection dip is due to the excitation of quasimodes (modes associated with a complex frequency) leading to quasi-total absorption. We have fabricated large area samples made of chromium nanorod gratings on top of Si/Cr layers deposited on silicon substrate. Measurements by Fourier transform spectrophotometry show good agreement with finite element simulations. A quasimodal expansion method is applied to obtain a minimal resonant model that fits well full wave simulations and that highlights excitation conditions of the modes. © 2014 Optical Society of America.


Vial B.,École Centrale Marseille | Commandre M.,École Centrale Marseille | Zolla F.,École Centrale Marseille | Nicolet A.,École Centrale Marseille | Tisserand S.,Silios Technologies
AIP Conference Proceedings | Year: 2011

We analyze diffraction gratings via their resonances by a direct determination of the eigenmodes and the complex eigenfrequencies using a finite element method (FEM), that allows to study mono- or bi-periodic gratings with a maximum versatility: complex shaped patterns, with anisotropic and graded index material, under oblique incidence and arbitrary polarization. In order to validate our method, we illustrate an example of a four layer dielectric slab, and compare the results with a specific method that we have called tetrachotomy, which gives us numerically the poles of the reflection coefficient (which corresponds to the eigenfrequencies of the structure). © 2011 American Institute of Physics.


Vial B.,Fresnel Institute | Vial B.,École Centrale Marseille | Zolla F.,Fresnel Institute | Zolla F.,Aix - Marseille University | And 5 more authors.
Optics Express | Year: 2012

We propose an Adaptive Perfectly Matched Layer (APML) to be used in diffraction grating modeling. With a properly tailored co-ordinate stretching depending both on the incident field and on grating parameters, the APML may efficiently absorb diffracted orders near grazing angles (the so-called Wood's anomalies). The new design is implemented in a finite element method (FEM) scheme and applied on a numerical example of a dielectric slit grating. Its performances are compared with classical PML with constant stretching coefficient. © 2012 Optical Society of America.


Patent
Silios Technologies | Date: 2015-08-24

A wavelength spectroscopy device includes, on a substrate, a filter cell CF constituted by two mirrors separated by a spacer membrane, the filter cell being made up of a plurality of interference filters. Furthermore, the device also includes an emission cell CE having a plurality of emission sources, each of the sources being associated with one of the interference filters.


Patent
Silios Technologies | Date: 2011-07-18

The invention relates to an optical probe including: Furthermore, the second cell C2 has a second emitter module LED2, the second detector module D2 is suitable for producing a second detection signal, and the first detector module D1 is suitable for producing a second monitoring signal for monitoring the second emitter module LED2.

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