D. Pagnoux - Academia.edu (original) (raw)

Papers by D. Pagnoux

We analyse the polarimetric response of fiber Bragg gratings involved in a fiber-based resonant m... more We analyse the polarimetric response of fiber Bragg gratings involved in a fiber-based resonant microscanner designed to produce polarimetric images of biological tissues through an endoscope for medical diagnosis. The intrinsic birefringence of the grating is measured and its detrimental consequences on the measured values are discussed. Solutions able to overcome this problem are proposed, paving the way for the fabrication of the very first polarimetric endomicroscope.

Journal of biomedical optics, 2016

This paper reports a technique based on spectrally differential measurement for determining the f... more This paper reports a technique based on spectrally differential measurement for determining the full Mueller matrix of a biological sample through an optical fiber. In this technique, two close wavelengths were used simultaneously, one for characterizing the fiber and the other for characterizing the assembly of fiber and sample. The characteristics of the fiber measured at one wavelength were used to decouple its contribution from the measurement on the assembly of fiber and sample and then to extract sample Mueller matrix at the second wavelength. The proof of concept was experimentally validated by measuring polarimetric parameters of various calibrated optical components through the optical fiber. Then, polarimetric images of histological cuts of human colon tissues were measured, and retardance, diattenuation, and orientation of the main axes of fibrillar regions were displayed. Finally, these images were successfully compared with images obtained by a free space Mueller micros...

Multiphoton Microscopy in the Biomedical Sciences XVI, 2016

The influence of a static electric field on a non-polar molecule has been studied by means of mul... more The influence of a static electric field on a non-polar molecule has been studied by means of multiplex coherent anti-Stokes Raman scattering (M-CARS). A parallel measurement of electric field induced second harmonic generation (EFISHG) has also been led. Both techniques suggest a reorientation of the molecule due to the presence of an electric field. This phenomenon can be used to increase the chemical selectivity and the signal to non-resonant background ratio, namely, the sensitivity of the M-CARS spectroscopy.

Novel Optical Systems Design and Optimization VII, 2004

Microstructured optical fibers (MOFs) are optical fibers having a periodic air-silica cross-secti... more Microstructured optical fibers (MOFs) are optical fibers having a periodic air-silica cross-section. The air holes extend along the axis of the fiber for its entire length. The core of the fiber is formed by a missing hole in the periodic structure. Remarkable properties of ...

Procedia - Social and Behavioral Sciences, 2004

The second mode extinction wavelength of air-silica microstructure optical fibers is measured by ... more The second mode extinction wavelength of air-silica microstructure optical fibers is measured by means of a method based on the azimuthal analysis of the far-field at the fiber exit. The fiber curvature influence is characterized.

Optics Letters, 2016

We experimentally demonstrate that pumping a graded-index multimode fiber with sub-ns pulses from... more We experimentally demonstrate that pumping a graded-index multimode fiber with sub-ns pulses from a microchip Nd:YAG laser leads to spectrally flat supercontinuum generation with a uniform bell-shaped spatial beam profile extending from the visible to the mid-infrared at 2500 nm. We study the development of the supercontinuum along the multimode fiber by the cutback method, which permits us to analyze the competition between the Kerr-induced geometric parametric instability and stimulated Raman scattering. We also performed a spectrally resolved temporal analysis of the supercontinuum emission.

$Research paper thumbnail of Fiber Bragg grating photowriting in microstructured optical fibers for sensing application based on refractive index measurement$

Proceedings of SPIE, 2005

In this paper we present results relative to Fiber Bragg Grating (FBG) photowritten in two kinds ... more In this paper we present results relative to Fiber Bragg Grating (FBG) photowritten in two kinds of Ge-doped microstructured optical fiber cores devoted to sensing applications. A cross comparison between theoretical and experimental modal field patterns is carried out. We present the first values of spectral sensitivity of Bragg grating, in relation to the refractive index of the substance inserted into the holes.

Pure and Applied Optics: Journal of the European Optical Society Part A, 1997

ABSTRACT We present a new experimental set-up capable of providing measurements of both the cut-o... more ABSTRACT We present a new experimental set-up capable of providing measurements of both the cut-off wavelength and the mode field radius of monomode optical fibres. The work consists in an original implementation, by means of a single experimental device, of two efficient methods conceived previously in our laboratory: the azimuthal far-field analysis technique for and the analysis of the autocorrelation function of the far field for . Two components (a mirror and a small screen pierced by a narrow slit) are fixed or rotated at the output of the fibre tested, to suitably filter the far field, according to the required parameter. This parameter is finally computed from the temporal variations of the power detected after the slit. The results obtained for both and are demonstrated to be precise and reliable. The measurements are self-referenced and can be achieved for any length of fibre as well as for fibres in cables or installed optical links.

Electronics Letters, 1991

ABSTRACT The LP1,n mode family exhibits an azimuthal dependence of mode conversion at a misaligne... more ABSTRACT The LP1,n mode family exhibits an azimuthal dependence of mode conversion at a misaligned splice or connectors. This property leads to an accurate method for centring monomode and multimode connectors based on LP11 mode rotation.

Optics letters, 2009

Polarization images were obtained using a flexible optical fiber device. The endoscopic technique... more Polarization images were obtained using a flexible optical fiber device. The endoscopic technique is based on the real-time compensation of the birefringence of the standard fiber by means of a miniaturized Faraday rotator. Based on a Jones formalism analysis, specific signal processing allows one to extract both the phase retardation and the degree of polarization of the light backscattered by a remote target.

Novel Techniques in …, 2009

... Jérôme Desroches, Dominique Pagnoux, Fredéric Louradour, Eric Suran, Julien Brévier, Alain Ba... more ... Jérôme Desroches, Dominique Pagnoux, Fredéric Louradour, Eric Suran, Julien Brévier, Alain Barthélémy Université de Limoges ; Centre National de la Recherche ... Lett., 31, 2018-20 (2006) [6] M. Davenne, C.Custody, P. Charneau and PM Lledo, "In vivo imaging of migrating ...