CROOKES'S LENSES.

Smart Lenses

Focus + context techniques are widely used for the efficient visualization of large data sets. However, the corresponding adaptation of the representation to the task at hand is not trivial, requiring a suitable model of the visualization goal. One type of focus + context technique is the use of lenses, interactive tools that modify the visualization in a locally confined region and can be ’sta...

Devil's lenses.

In this paper we present a new kind of kinoform lenses in which the phase distribution is characterized by the "devil's staircase" function. The focusing properties of these fractal DOEs coined devil's lenses (DLs) are analytically studied and compared with conventional Fresnel kinoform lenses. It is shown that under monochromatic illumination a DL give rise a single fractal focus that axially ...

Double lenses

The analysis of the shear induced by a single cluster, acting as a gravitational lens, on the images of a large number of background galaxies is all centered around the curl-free character of a well-known vector field that can be derived from the data; in particular, the mass reconstruction methods, currently producing many interesting astrophysical applications, are all based on this tensorial...

[contact Lenses].

Gravitational Lenses

Gravitational lenses are becoming a precious mean of probing the matter distribution in the Universe. From the search of matter in the Galactic halo to the study of the large-scale structures of the Universe, the gravitational lens effects offer a unique alternative to light surveys and are now widely used. This evolution is due in particular to the use of new observation devices, such as the w...