At the Photonics West conference taking place in San Francisco this week, Nanoscribe GmbH, a spin-off of Karlsruhe Institute of Technology (KIT), presented the world’s fastest 3D printer of micro- and nanostructures. With this printer, smallest three-dimensional objects, often smaller than the diameter of a human hair, can be quickly manufactured with high resolution. The printer is based on a novel laser lithography method.
The 3D laser lithography systems developed by Nanoscribe – the spin-off can still be found on KIT’s Campus North – are now used for research by KIT and scientists worldwide. For example, Nanoscribe systems are used to print polymer waveguides reaching data transfer rates of more than 5 terabits per second. Biosciences applications include production of tailored scaffolds for cell growth studies. In materials research, functional materials with enhanced performance are being developed for lightweight construction to reduce the consumption of resources.
Using this novel lithography method, printing speed is increased by factor of about 100x. This increase in speed results from the use of a galvo mirror system, a technology that is also applied in laser show devices or scanning units of CD and DVD drives. Reflecting a laser beam off the rotating galvo mirrors facilitates rapid and precise laser focus positioning.
“We are revolutionizing 3D printing on the micrometer scale. Precision and speed are achieved by the industrially established galvo technology. Our product benefits from more than one decade of experience in photonics, the key technology of the 21st century,” according to Martin Hermatschweiler, the managing director of Nanoscribe.
The direct laser writing technique underlying the 3D printing method is based on two-photon polymerization. Ultra-short laser pulses polyme
rize photosensitive materials in the laser focus. Depending on the photosensitive material chosen, the exposed or unexposed volume only is dissolved. After a developer bath, these written areas remain as self-supporting micro- and nanostructures.
By means of the galvo technology, three-dimensional micro- and nanostructures can be printed rapidly and, hence, also on large areas at least in principle. At highest resolution, however, the scanning field is limited physically to a few 100 µm due to the optical properties of the focusing objective. The respective scanning fields have to be connected seamlessly and accurately by so-called stitching. As a result areas can be extended nearly arbitrarily.
his is ensured by high-precision stages as well as a patented autofocus function. In order to make structures tall, DiLL completes the recipe with unrivaled resolution.
To ensure the high precision of Nanoscribe’s directlaser writing (DLW) process even at high writing speeds, an accurate coordination of beam deﬂection, sample movement and laser intensity modulation must be secured – at all times during the writing process! A sophisticated control system consisting of matched optics, electronics and software has been developed.
The galvo technology is an essential ingredient to speed up 3D micro- and nano-fabrication. In order to make structures large-area, it additionally needs a sophisticated stitching of adjacent tiles.