Nanoscribe's technology for the fabrication of three-dimensional micro- and nanostructures in photo-sensitive materials is based on "direct laser writing", i.e., a non-linear two-photon absorption process. Many resins that polymerize when exposed to UV-light can undergo similar chemical reactions when two photons of near-infrared light are absorbed simultaneously. A necessary condition for this effect to occur is a sufficiently high light intensity that is provided by an ultrashort pulse laser. Typically, the laser is focused into the resin and the two-photon polymerization (TPP) is triggered only in the focal spot volume. As 3D analogon to a pixel, the volume counterpart is called voxel.
The effect of two-photon induced photopolymerization was first reported in 1965 by Pao and Rentzepis* and since then has become a valuable tool for micro fabrication. It enables the manufacturing of micro- and meso-scaled parts with a high shape- and functional-complexity in various positive tone photoresists. Read More »
Multiphoton lithography allows also subtractive manufacturing of positive tone resists. Nonlinear light absorption triggers a local "depolymerization" of the material that can be easily washed away in a developer. Read More »
... but does not have to end there. For many fields of application in science and industry, the choice of polymer as a printing medium is already sufficient. But some applications demand materials that can not directly be processed by two-photon polymerization. In those case, there are several inversion and casting techniques that allow the replication of 3D structures in metals, silicon, silica or PDMS.
The versatility of the patterning technology makes it a useful tool for scientific and industrial applications. By colaborating with industrial partners within the context of funded projects, Nanoscribe matches the technology to the demands of industry. Read More »
Laser-induced Production of Free Radicals in Organic Compounds 6(1965)