3D printer creates nanostructures

Eggenstein-Leopoldshafen, Germany - Nanoscribe GmbH, a spin-off company from Karlsruhe Institute of Technology (KIT), has introduced a laser lithography system that can create three-dimensional objects smaller than a human hair. The company claims the new unit has the highest resolution of any commercial 3D printer

The printer gets its ability from a combination of mirrors and chemistry. The process begins with any of several different polymers, chalcogenide glasses, or resists in vat. The materials all have one thing in common: they require activation of two photons rather than one before they begin to polymerize into solids. Only the very center of the laser beam has enough energy to activate both photons. Because this part of the beam is so small, it polymerizes only the narrowest of swaths of material a time.

In the past, this took a fair amount of time. The unit's galvo-mirror system changed that. It is a high-precision cousin of similar units used in laser light shows and laser marking systems. Using two rotating mirrors to direct the laser beam with nanoscale precision, it can polymerize segments at higher speeds than in the past. In fact, Nanoscribe claims its new model is 100 times faster than its previous machine.

A piezoelectric scanning stage complements the galvo mirrors. It moves the substrate in all three dimensions with outstanding precision relative to the laser focus position, a must when dealing with nanoscale features that will waver out of specification with the slightest vibration.

Nanoscribe is not the only developer that has caught onto high-precision galvo mirrors. This past December, Vienna University of Technology researcher Juergen Stampfl used galvo mirrors to build a 3D system that could lay down lines a few hundred nanometers wide at rates of 5 m/sec. That system is not commercially available.

Karlsruhe Institute of Technology www.kit.de has used the Nanoscribe system to build optical devices and circuits. Other uses range from 3D-labs on-a-chip and microfluidic systems to microscale rapid prototyping and creation of mechanical microstructures.