Two-photon polymerisation of novel shapes using a conically diffracted femtosecond laser beam

Sub-micron ring, pillar and wall structures were written by two-photon polymerisation of a sol–gel resin using a femtosecond laser beam which was shaped using internal conical diffraction. The ring structure was written using a demagnified image of the ring-shaped beam which arises in conical diffraction of a narrow light beam. The pillar and wall structures were produced by imaging the Bessel beam formed by conical diffraction in combination with a converging lens.

Research highlights
► Two-photon polymerisation was performed with a conically diffracted pulsed laser beam.
► Ring, pillar and grid structures were written in a sol–gel resin.
► Polymerised rings had micron scale diameters and sub-micron thickness.
► Pillar and grid wall height to width ratio varied between five and eight to one.