+Present address: Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Kamigori, Hyogo 678-1297, Japan.

1Tests with the kinoform lenses suggested that a size of <6 µm could have been achieved without source size limits.

2When the full aperture is used, the combination of coherently, phase-preserving, and incoherently transported beams might lead to complex fine structure within the focal spot.