Nanoscribe has recently introduced Dip-in Laser Lithography (DiLL) allowing for two-photon polymerization with constant optical aberrations (News and Reviews Sept 2011).
The objective lens is directly dipped into a liquid photoresist serving as immersion and photosensitive medium at the same time. Hereby, even in case of non-index-matched photoresist material, the homogeneity of the writing process is preserved along the optical axis. However, the focal intensity distribution is still dependent on the refractive index of the photosensitive material. For diffraction-limited focal spots, the photoresist needs to be index-matched. Our novel photoresist IP-Dip is specially developed to have a refractive index of about 1.52 at the relevant laser wavelength matching that of the focusing optics. Accordingly, IP-Dip fulfills the requirement for ideal focusing, and hence, allows for highest resolution in optical dip-in lithography.
Application of ip-dip
The group of Prof. Martin Wegener at the Karlsruhe Institute of Technology, Germany, has recently introduced novel routes for 3D mechanical metamaterials2,3. Impressive examples of their work are so-called pentamode metamaterials that the group has realized experimentally for the first time. The depicted electron micrographs show the filigree pentamode structures which have impeccable fabrication quality. These artificial materials can be applied for three-dimensional transformation elastodynamics in analogy with transformation optics. With a volume filling fraction as low as ~1% the authors also demonstrated the possibility to manufacture ultralight materials.
Scanning electron micrographs of pentamode mechanical metamaterials fabricated by using Dip-in Laser Lithography and Nanoscribe’s novel resist IP-Dip. By courtesy of Prof. Martin Wegener´s group, Karlsruhe Institute of Technology (KIT)
(2) M. Kadic et al. “On the practicability of pentamode mechanical metamaterials”, Appl. Phys. Lett. 100, 191901 (2012).
(3) T. Bückmann et al. “Tailored 3D Mechanical Metamaterials Made by Dip-in Direct-Laser-Writing Optical Lithography”, Adv. Mater. 24, 2710 (2012).