Open AccessFocusing of beams into subwavelength area in an inhomogeneous medium
Author(s) -
Nikolai I. Petrov
Publication year - 2001
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.9.000658
Subject(s) - paraxial approximation , optics , physics , wavefront , diffraction , aperture (computer memory) , gaussian , beam (structure) , refractive index , gaussian beam , geometrical optics , wave propagation , light beam , quantum mechanics , acoustics
Propagation and focusing of nonparaxial Gaussian beams with spherical wavefront in a graded-index medium are investigated using quantum-theoretical method of coherent states. Explicit expressions for the trajectory and width of a beam taking into account all correction terms to the paraxial approximation have been obtained. Electromagnetic field distributions in longitudinal and lateral directions are simulated. Diffraction of strongly focused high-aperture wave beams is investigated theoretically. The ratio of intensities of evanescent and propagating fields is calculated for different values of focused spot.