Ultrashort ring-Airy laser beams for advanced materials engineering

Ultrashort ring-Airy laser beams with tunable characteristics are experimentally generated and employed for the advanced fabrication of large 3D structures with high resolution using multiphoton polymerization. These beams can be adjusted to abruptly autofocus over an extended range of working distances while keeping almost invariant their voxel shape and dimensions. This striking property together with the real-time controlled focus tuning, through a spatial light modulator, make them ideal candidates for long range multiphoton polymerization. Moreover, the paraxial ring-Airy beams can approach the wavelength limit when scaling down, while observing a counterintuitive, strong enhancement of their focal peak intensity. Using numerical simulations, we show that this behavior is a result of the coherent constructive action of paraxial and nonparaxial energy flow.