Light distribution in the focal regions of a lens in a parabolic index medium.
We present a detailed examination of the light distribution near the foci of a plane wave focused by a diffraction-limited lens in a parabolic index medium. We show how the light distribution changes as the degree of grading is varied, and we obtain explicit very simple expressions for intensity widths. Suitable scaling reveals that the results depend on only a very few dimensionless parameters, the most crucial involving the ratio of the focusing power of the lens to the self-focusing power of the medium itself. We also investigate the symmetry of the light distribution and describe a new effect which has no analog with focusing in homogeneous media.
Bertilone
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