Demonstration of an elliptical plasmonic lens illuminated with radially-like polarized field.

We demonstrate an elliptically symmetric plasmonic lens that is illuminated by a radially-like polarization field. This illumination function is TM polarized with regard to the plasmonic lens, ensuring optimum coupling of the incident light into surface plasmons polaritons. The structure is analyzed theoretically by using the Green function approach, and a finite difference time domain simulation.

Wavefront reconstruction by spatial-phase-shift imaging interferometry.

Common-path imaging interferometers offer some advantages over other interferometers, such as insensitivity to vibrations and the ability to be attached to any optical system to analyze an imaged wavefront. We introduce the spatial-phase-shift imaging interferometry technique for surface measurements and wavefront analysis in which different parts of the wavefront undergo certain manipulations in a certain plane along the optical axis. These manipulations replace the reference-beam phase shifting of existing interferometry methods.

Spatial phase-shift interferometry--a wavefront analysis technique for three-dimensional topometry.

We describe a new wavefront analysis method, in which certain wavefront manipulations are applied to a spatially defined area in a certain plane along the optical axis. These manipulations replace the reference-beam phase shifting of existing methods, making this method a spatial phase-shift interferometry method. We demonstrate the system's dependence on a defined spatial Airy number, which is the ratio of the characteristic dimension of the manipulated area and the Airy disk diameter of the optical system.

Small-focus integral fiber lenses: modeling with the segmented beam-propagation method and near-field characterization.

Tapered- and straight-core fiber microlenses of hyperbolic shape are studied with the segmented beam propagation method (Se-BPM). This new formulation extends to a large scale the finite-difference time-domain method for calculating propagation of the wave field in guiding systems. It is based on partitioning an entire computational domain into subdomains along the direction of propagation.

Topographic profiling and refractive-index analysis by use of differential interference contrast with bright-field intensity and atomic force imaging.

A methodology is described for phase restoration of an object function from differential interference contrast (DIC) images. The methodology involves collecting a set of DIC images in the same plane with different bias retardation between the two illuminating light components produced by a Wollaston prism. These images, together with one conventional bright-field image, allows for reduction of the phase deconvolution restoration problem from a highly complex nonlinear mathematical formulation to a set of linear equations that can be applied to resolve the phase for images with a relatively large number of pixels.

Generalized method for wave-front analysis.

We suggest and demonstrate a new method for wave-front analysis based on common-path phase-shift interferometry. We introduce a formalism and an iterative mathematical algorithm in which the wave front is transformed, modified, and inversely transformed. The resulting intensity data are sufficient to reconstruct the entire wave front.