Transverse variation of partially coherent axicon lines

Abstract

Di ractive axicons operating in spatially partially coherent light can be designed non-iteratively, on the basis of asymptotic wave theory, to produce focal lines with prescribed on-axis intensity pro®les. In this paper we analyse the transverse intensity variation of these axicon lines, concentrating on relatively coherent beams. By Taylor expansion, a way is found to approximate the transverse intensity pro®le, without the demanding numerical integration otherwise needed. From this expression, also the width of the focal line as a function of position on the optical axis can be easily found. As now both this width pro®le and the on-axis intensity pro®le can be determined, the two most important features of the partially coherent axicon focal line have been characterized.

Shaping the on-axis intensity profile of generalized Bessel beams by iterative optimization methods

“…Finally, the design for partially coherent source and oblique illumination introduced in the thesis [27] were of interest in applications using Bessel beams. It might be worth further investigating the use of the GA iterative design process under those conditions.…”

“…However, geometric optics cannot treat the diffraction effect; for example, the intensity oscillation caused by the edge blocking of a beam [19] cannot be evaluated during the design process. Anna Thaning [27] made an improvement by using stationary-phase method to design axicons with the inclusion of the oscillation property; the on-axis intensity oscillations were smoothed via the beam apodization. Generalized axicons were also designed for partially coherent source or oblique illumination for different applications [27].…”

“…Anna Thaning [27] made an improvement by using stationary-phase method to design axicons with the inclusion of the oscillation property; the on-axis intensity oscillations were smoothed via the beam apodization. Generalized axicons were also designed for partially coherent source or oblique illumination for different applications [27]. However, the apodization needs an amplitude modulation and its capability for smooth the oscillations may be limited.…”