Beam-preshaping axicon focusing

An approach to efficient axially symmetric focusing of a light beam to an extended line segment is studied wherein the on-axis intensity and the scale of transverse intensity distribution can be controlled precisely and simultaneously at any point of the segment. Schematic realization is based on employing two phase-only optical components in tandem, the first of which, with a disk form, performs prior central light beam shaping and marginal correction to smooth the edge slopes, while the second one, with an annular form, is used for the appropriate axicon-type focusing of a light beam to the segment. An instance is given of converting a collimated Gaussian laser beam into an oscillation-free nondiffracting zero-order Bessel beam reproduced an a finite interval. (C) 1998 Optical Society of America [S0740-3232(98)01312-X].