Diffraction at binary microaxicons in the near field

Abstract

This paper discusses the formation of the central light spot by means of a binary diffraction axicon with high numerical aperture, using a difference method of solving Maxwell's equations in the temporal region. It is shown that the broadening of the central light spot that unavoidably appears when the beam that illuminates the axicon is linearly polarized can be compensated by introducing a linear phase singularity (perpendicular to the polarization direction) into the beam. A very compact, weakly broadened light spot whose size in the immediate vicinity of the surface of the optical element is 37% less than the diffraction limit can be formed in this case by varying the substrate thickness.

On the 50th Birthday of Pavel G. Serafimovich

“…In subsequent years P.G. Serafimovich used the obtained foundation for creating methods of investigating a variety of DOEs in the framework of asymptotic methods and computational experiment [15][16][17][18][19][20].…”

Diffractive Axicons to Increase the Efficiency of Solar Cells

“…Thus, onaxis light segment which has a full width at a half maximum of равна 0,36λ/NA ( is a wavelength, NA = sin -numerical aperture of the axicon), that is significantly less than Airy disk diameter which is produced with a lens with the same numerical aperture [10][11][12][13][14]. Moreover, a depth of focus is much greater for an axicon than for a lens even for high numerical apertures [13,14]. This fact makes axicons to be useful for those systems where it is difficult to precisely adjust all distances.…”

For the anniversary of professor S.N. Khonina

“…A remarkable fact was discovered in the course of studies on sharp focusing. It was the possibility to overcome the diffraction limit in the near field zone using the axicons with subwavelength period [68][69][70][71][72][73]. The generation of the longitudinal component of electromagnetic field on the optical axis in the focal region while entering into the beam with linear and circular polarization of the vortex phase in conditions of sharp focusing was theoretically shown.…”