The three-dimensional intensity distribution in the focal region of lenses with filters consisting of arrays of rings is investigated in the paraxial Debye regime. The axial behavior can exhibit a variety of different effects.

Focal distribution for superresolving toraldo filters

The short range revival of an arbitrary monochromatic optical field, which propagates in a quadratic GRIN rod, is a well-known effect that is established assuming the first-order approximation of the propagation operator. We discuss the revival and multiple splitting of an off-axis Gaussian beam propagating to relatively long distances in a quadratic GRIN medium. These effects are obtained assuming the second-order approximation of the propagation operator in this medium.

Revival and splitting of a Gaussian beam in gradient index media

A generalization of the Talbot effect to the case of a tapered gradient-index medium for nonuniform and uniform illumination is considered. Self-image positions are changed by a function depending on the taper profile, the illumination, and the periodic object. An analogy with the conventional lens-imaging formula for both types of illumination is presented.

Talbot effect in a tapered gradient-index medium for nonuniform and uniform illumination

A generalization of the fractional Talbot effect to the case of a tapered gradient-index medium for uniform illumination is considered. A unit cell of the fractional Talbot image contains the superposition of unit cell images of the periodic object.

Fractional Talbot effect in a tapered gradient-index medium: unit cell

The wavelength-scale features in holey fibers lead to novel properties including endlessly single-mode guidance and anomalous dispersion below 1.3 /spl mu/m. Fundamental concepts and recent progress are reviewed, ranging from fabrication and modelling to devices and applications.

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Holey fibers: new possibilities for guiding and manipulating light

A novel analysis of specially designed photonic crystal fibers accounts for the existence of endlessly single-mode structures with flattened dispersion. Our approach permits to control the fiber dispersion in terms of its geometrical parameters.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Designing a photonic crystal fiber with flattened dispersion

We discuss the formation of self-images in an optical fiber with quadratic refractive index variations, and in its lens tandem equivalent setup. We identify two family sets of self-images. The first family set has geometrical magnification less or greater than unity. The other family set is obtained by longitudinal replication, with unit magnification of the first family set.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Self-imaging in GRIN media

A technique is presented for improving 3-D resolution in confocal scanning microscopy. The technique is based on the equal contribution to the image of the illuminating and the collecting lenses. It is proposed, then, to apodize such lenses with complementary filters. The combined action of both filters produces a narrowness of the point spread function of the system both in the image plane, and along the optical axis.

Improvement of three-dimensional resolution in confocal microscopy

We have combined a fusion-pulling technique and a standard metal-coating technique to fabricate in-line single-mode fiber filters, polarizers and sensors. The reduction of the core and cladding diameters in a tapered fiber causes the evanescent field to extend beyond the outer boundary. Thus, when a metal film is evaporated on a tapered fiber, the surface plasma modes cause coupling to the fiber mode.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Tapered optical fiber devices

A method for the calculation of the axial illuminance and chromaticity as polychromatic merit functions of optical imaging systems is presented. We show that the Wigner distribution function of the pupil of the system allows us to obtain all the monochromatic components needed for the calculation of these parameters. From this single phase-space representation, the merit functions can be obtained in a polar fashion for a variable spherical and longitudinal chromatic aberrations. Numerical examples for an axially apodizing filter are shown.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Enrique Silvestre-Mora

Papers

Designing a photonic crystal fiber with flattened dispersion

Self-imaging in GRIN media

Improvement of three-dimensional resolution in confocal microscopy

Tapered optical fiber devices

Polychromatic merit functions in terms of the Wigner distribution function