Three-dimensional micro- and nanostructuring with two-photon polymerisation

Two-photon polymerisation (2PP) of inorganic-organic hybrid polymers (ORMOCER1s) is demonstrated as a very promising approach for the fabrication of complex three-dimensional micro and nanostructures. Optical and mechanical properties of ORMOCER1 together with the 2PP-process open up new options for the design and packaging, e.g. of photonic devices. The 2PP-process employs ultrashort pulses which are focused into the volume of a photopolymer, being transparent at the laser wavelength. Solidification is performed in a highly localised volume due to the quadratic dependence of the two-photon absorption rate on the laser intensity. The polymerisation occurs along the 3D-trace of the focus allowing the fabrication of any computer generated 3D-structure by direct laser "recording". This technology can be used for rapid prototyping and low-cost fabrication of micro- and nanostructured components. Achieving spatial resolutions down to ~100 nm, even optical components can be produced and integrated to compact devices. This paper provides a discussion of two-photon polymerisation technique and examples of microfabrication.