Concept

Axe optique

Publications associées (15)

Aberrations analysis of a Focused Plenoptic Camera

A Focused Plenoptic Camera in Galilean configuration is studied and its aberrations behavior is interpreted with the Nodal Aberration Theory (NAT). Sequential ray tracing is applied to individual optical channels constituted by the camera objective and ind ...

2018

Cyanine platelet single crystals: growth, crystal structure and optical spectra

Frank Nüesch, Jakob Heier, Antonia Neels

Crystalline organic semiconducting materials are much in demand for multiple electronic and optoelectronic device applications. Here, solution grown ultrathin rhombic crystals of a trimethine carbocyanine anionic dye are used to establish relationships bet ...

Royal Society of Chemistry2018

Distributed shape sensing using Brillouin scattering in multi-core fibers

Luc Thévenaz, Marcelo Alfonso Soto Hernandez

A theoretical and experimental study on the response of Brillouin scattering in multi-core optical fibers (MCF) under different curving conditions is presented. Results demonstrate that the Brillouin frequency shift of the off-center cores in MCF is highly ...

Optical Society of America2016

Landmark Detection for Fusion of Fundus and MRI Toward a Patient-Specific Multimodal Eye Model

Meritxell Bach Cuadra

Ophthalmologists typically acquire different image modalities to diagnose eye pathologies. They comprise, e.g., Fundus photography, optical coherence tomography, computed tomography, and magnetic resonance imaging (MRI). Yet, these images are often complem ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Experimental and theoretical study of the Gouy phase anomaly of light in the focus of microlenses

We report on the Gouy phase anomaly of light in the focus of cylindrical and spherical microlenses. The prime subject of our study concerns a discussion of how the very small size of microlenses affects the phase properties of light in their foci. We put emphasis on determining the amount of the Gouy phase shift for line and point foci within the limited axial space. Contrary to macroscopic lenses, the optical properties of microlenses are strongly governed by the effect of diffraction when their size tends

Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft2013

Enhancement of extended depth of field by digital focusing

Theo Lasser

With the use of a Bessel-like illumination beam produced by an axicon lens an extended depth of field can be achieved. The resulting illumination pattern exhibits a strong central lobe extending over 300um along the optical axis without diffraction. Here we present a fast digital focusing algorithm to correct for remaining out of focus artifacts, manifest in sidelobes for out of focus scatterers, due to the decoupled Gaussian detection. The waist of the detection in the focal plane is 2.1um, with a Rayleigh

2008

Sub-cellular quantitative optical diffraction tomography with digital holographic microscopy

Christian Depeursinge, Tristan Colomb, Etienne Cuche, Florian Charrière

Digital holographic microscopy (DHM) is an interferometric technique, providing quantitative mapping of the phase shift induced by semi- transparent microscopic specimens, such as cells, with sub-wavelenght resolution along the optical axis. Thanks to actual PCs and CCDs, DHM provides nowadays cost-effective instruments for real-time measurements at very high acquisition rates, with sub-micron transverse resolution. However, DHM phase images do not reveal the three-dimensional (3D) internal distribution of

SPIE2007

Microlenses metrology with digital holographic microscopy

Christian Depeursinge, Tristan Colomb, Etienne Cuche, Florian Charrière, Frédéric Montfort

Digital holographic Microscopy (DHM) is an imaging modality reconstructing the wavefront in a numerical form, directly from a single digitalized hologram. It brings quantitative data derived simultaneously from the amplitude and phase of the complex reconstructed wavefront diffracted by the object and it is used to determine the refractive index and/or shape of the object with accuracy in the nanometer range along the optical axis. DHM comprises a microscope objective to adapt the sampling capacity of the c

SPIE2005

Digital Holographic Microscopy applied to Metrology

Christian Depeursinge, Tristan Colomb, Etienne Cuche, Florian Charrière, Frédéric Montfort

We report on a method called Digital Holographic Microscopy (DHM) for the numerical reconstruction of digital holograms taken with a microscope. It allows for simultaneous amplitude and quantitative phase contrast imaging. The reconstruction method computes the propagation of the complex optical wavefront diffracted by the object and is used to determine the refractive index and/or shape of the object with an accuracy in the nanometer range along the optical axis. A single hologram is needed for reconstruct

SPIE2004

Extended Depth-of-Focus for Multi-Channel Microscopy Images: A Complex Wavelet Approach

Michaël Unser, Daniel Sage

Microscopy imaging often suffers from limited depth-of-focus. However, the specimen can be “optically sectioned” by moving the object along the optical axis; different areas appear in focus in different images. Extended depth-of-focus is a fusion algorithm that combines those images into one single sharp composite. One promising method is based on the wavelet transform. In this paper, we show how the wavelet-based image fusion technique can be improved and easily extended to multi-channel data. First, we pr

IEEE2004

Complex Wavelets for Extended Depth-of-Field: A New Method for the Fusion of Multichannel Microscopy Images

Michaël Unser, Daniel Sage

Microscopy imaging often suffers from limited depth-of-field. However, the specimen can be “optically sectioned” by moving the object along the optical axis. Then different areas appear in focus in different images. Extended depth-of-field is a fusion algorithm that combines those images into one single sharp composite. One promising method is based on the wavelet transform. Here, we show how the wavelet-based image fusion technique can be improved and easily extended to multichannel data. First, we propose

Wiley-Liss2004

The phases of Cs3Bi2I9 between RT and 190 K

Gervais Chapuis

The structure of Cs3Bi2I9 has been refined to R = 0.0165 on the basis of X-ray diffraction measurements at T = 290 K (STOE IPDS diffractometer; MoKalpha-radiation; 296 nonequivalent reflection with I > 2 sigma(I)). The absorption correction was accounted for by the Gaussian method. The parameters of the hexagonal unit cell are: a = 8.409(1) Angstrom and c = 21.243(5) Angstrom; space group P6(3)/mmc. The structure consists of identical perovskite-like layer fragments described by the general formula A(3)B(2)

1999

Optical fibers with patterned ZnO/electrode coatings for flexural actuators

Nava Setter

A fiber-based flexural actuator was developed using a patterned piezoelectric ZnO/electrode fiber coating on a standard telecommunications optical fiber. The actuator was composed of a concentric inner Cr/Au electrode, a thick sputtered ZnO coating, and an outer Cr/Au electrode. Using standard photolithography, 30-mu m wide gaps in one of the electrodes were patterned along 2-cm lengths parallel with the fiber axis. This device can be driven in a bimorph mode. It was demonstrated that a split electrode actu

1999

Optical tomography at the microscopic scale by means of a numerical low coherence holographic technique

Christian Depeursinge, Etienne Cuche

We describe here a numerical application of the optical low- coherence holographic microscopy (OLCHM) technique. A low coherent source illuminates an object and the backscattered light interfere with a reference wave which optical path's length can be precisely adjusted. Holograms are recorded by a CCD camera and numerically reconstructed. With this technique optical tomography can be performed with a single scan along the optical axis. The transverse resolution of the reconstructed images mainly depends on

SPIE1996

Sputter deposited piezoelectric fiber coatings for acousto-optic modulators

Nava Setter, Hans Georg Limberger

All-fiber optical phase modulators were fabricated by coating standard telecommunication optical fibers with thin films of piezoelectric ZnO. Piezoelectric optical fiber coatings of PbZrxTi1-xO3(PZT) were also produced, and the actuation capability necessary for making optical fiber modulators is demonstrated. Both the ZnO and the PZT fiber coatings were deposited by reactive direct current magnetron sputtering of metal targets. The geometry of the sputtering system, fiber rotation, and reactive sputtering

1996

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Publications associées (15)