Three-dimensional microfabrication with femtosecond laser pulses

Investigations on two-photon polymerization of inorganic-organic hybrid materials initiated by femtosecond Ti:sapphire laser pulses are performed. The applied resins are designed for ultraviolet photo-lithography and contain photo-initiators sensitive to 390 nm radiation. These resins exhibit exceptionally good mechanical, optical, and chemical properties and can be microstructured by laser-enforced transition from liquid to solid state. These materials are transparent in the infrared, therefore, by tightly focusing femtosecond laser pulses into the volume of a liquid resin, two-photon polymerization can be initiated in a small focal region inside the liquid. First applications of this technique for the fabrication of three-dimensional microstructures and photonic crystals in inorganic-organic hybrid polymers with a structure size down to 200 nm and a periodicity of 450 nm are discussed.