Rr. Letfullin et Tf. George, Optical effect of diffractive multifocal focusing of radiation on a bicomponent diffraction system, APPL OPTICS, 39(16), 2000, pp. 2545-2550
It is shown for the first time, to our knowledge, that when a plane wave il
luminates a certain type of bicomponent optical system, consisting of two p
lane screens with circular apertures on a given optical axis, a multifocal
diffractive focusing effect can appear. Here the diffraction picture in the
focal planes represents the circular nonlocal bands of the Fresnel zones w
ith a bright narrow peak at the center, whose intensity can exceed by 6-10
times the value of the incident-wave intensity. The detected optical effect
is observed across a wide range of wavelengths, lambda = 0.4-10(3) mu m, a
nd ratios of the aperture diameters d(1) greater than or equal to 2d(2) = 2
5-1000 lambda, and it is also insensitive to changes in the medium of the w
ave propagation. For the large diameters of input holes, d(1) = 2d(2) > 100
lambda, or for wavelengths in the radio-frequency region of the spectrum,
the bicomponent diffraction system acts as a long-focus lens with a high-in
tensity Gaussian distribution of radiation, at times exceeding the initial
intensity, persisting at large distances (z = 1-100 cm) from the diffractio
n system. (C) 2000 Optical Society of America OCIS codes: 050.0050, 050.197
0, 220.3630, 220.2560, 220.4830, 080.5620.