Authors:
Frank Burmeister
Institute of Applied Physics, Friedrich-Schiller-Universita¨t Jena, D-07743 Jena, Germany and Fraunhofer Institute for Applied Optics and Precision Engineering IOF, D-07745 Jena, Germany

So¨nke Steenhusen
Ruth Houbertz
Fraunhofer Institute for Silicate Research ISC, D-97082 Wu¨rzburg, Germany

Uwe D. Zeitner
Stefan Nolte
Andreas Tu¨nnermann
Institute of Applied Physics, Friedrich-Schiller-Universita¨t Jena, D-07743 Jena, Germany and Fraunhofer Institute for Applied Optics and Precision Engineering IOF, D-07745 Jena, Germany

The fabrication of sub-100 nm feature sizes in large-scale three-dimensional (3D) geometries by two-photon polymerization requires a precise control of the polymeric reactions as well as of the intensity distribution of the ultrashort laser pulses. The authors, therefore, investigate the complex interplay of photoresist, processing parameters, and focusing optics. New types of inorganic– organic hybrid polymers are synthesized and characterized with respect to achievable structure sizes and their degree of crosslinking. For maintaining diffraction-limited focal conditions within the 3D processing region, a special hybrid optics is developed, where spatial and chromatic aberrations are compensated by a diffractive optical element. Feature sizes below 100 nm are demonstrated.