4pi Multiphoton Polymerization

We present a 4Pi multiphoton polymerization technique-a technique that, similar to microscopy, enables a significant improvement of the axial resolution of the fabricated features. We describe this technique in detail and present a numerical simulation analysis of the light intensity distribution in the focal plane as well as experimental results. Using the 1030 nm wavelength, we were able to achieve 150 nm height features, which is about three times shorter than that using the traditional excitation technique, resulting in nearly spherical voxels. Furthermore, we show that depending on the focusing conditions, it is also possible to fabricate periodic interference patterns along the illumination direction, which can be utilized for photonics applications.