Biomedical subjects

Jacques Duparré

Publications and source records attributed to Jacques Duparré.

5 recordsLinked to original sources

PubMed2005

Thin compound-eye camera.

An artificial compound-eye objective fabricated by micro-optics technology is adapted and attached to a CMOS sensor array. The novel optical sensor system with an optics thickness of only 0.2 mm is examined with respect to resolution and sensitivity. An optical resolution of 60 x 60 pixels is determined from captured images. The scaling behavior of artificial compound-eye imaging systems is analyzed. Cross talk between channels fabricated by different technologies is evaluated, and the influence on an extension of the field of view by addition of a (Fresnel) diverging lens is discussed. The lithographic generation of opaque walls between channels for optical isolation is experimentally demonstrated.

Animals↗

PubMed2004

Implementation of field lens arrays in beam-deflecting microlens array telescopes.

Laterally displaceable microlens array telescopes allow for variable and fast beam deflection. The generation of spurious light usually leads to a reduction of transfer efficiency with increasing displacement. We present the introduction of an array of field lenses on the back side of a recollimating microlens array that results in a reduced deflection angle dependency of transfer efficiency. A paraxial matrix formalism is used to prove the theoretical elimination of spurious light by use of a field lens array. The fabrication of well-aligned double-sided lens arrays by UV replication is discussed. Measurements of transfer efficiency with and without the use of field lens arrays are compared with the results of numerical wave-optic simulations.

Journal Article↗

PubMed2004

Artificial apposition compound eye fabricated by micro-optics technology.

By exploring micro-optical design principles and technology, we have developed an artificial apposition compound eye. The overall thickness of the imaging system is only 320 microm, the diagonal field of view is 21 degrees, and the f-number is 2.6. The monolithic device consists of an UV-replicated microlens array upon a thin silica substrate with a pinhole array in a metal layer on the back side. The pitch of the pinholes differs from that of the lens array to provide individual viewing angle for each channel. Theoretical limitations of resolution and sensitivity are discussed as well as fabrication issues and compared with experimental results. A method to generate nontransparent walls between optical channels to prevent cross talk is proposed.

Journal Article↗

PubMed2003

Micro-optical 1 x 4 fiber switch for multimode fibers with 600-microm core diameters.

The design, manufacture, and test of a 1 x 4 micro-optical fiber switch for multimode fibers with 600-microm core diameters are described. Microlens array telescopes allow for variable and fast beam deflection when the positions of the cylindrical microlens arrays relative to each another are altered by specially designed piezomechanical actuators. Standard achromats are used for collimation of light emitted by the input multimode fiber and for focusing of the deflected light onto a linear array of output multimode fibers. Design and assembly of micro-optical as well as of optomechanical components are discussed. Insertion loss and cross talk are measured, and the results are compared with those of numerical optical simulations. Measurements of switching time and long-term stability, as well as of thermal behavior, are also presented.

Journal Article↗

PubMed2003

Numerical wave optical analysis of microlens array telescopes and comparison with experimental results.

We present a numerical wave optical model to describe the complex behavior of coaxial and decentered microlens-array-based telescopes illuminated by an incoherent angular spectrum of plane waves. With the use of this model we have been able to observe major performance differences between Galilean and Keplerian setups, which to our knowledge were not described before. The results of the simulations are compared with experimental results; the images of multimode fiber end faces are characterized with respect to transfer efficiency and intensity distribution. The results are also explained by use of modified existing analytical models.

Journal Article↗