Laser Creates Cheaper Free-Form Optics
AACHEN, Germany, April 17, 2012 — A new cost-effective process for fabricating small batches of nonspherical glass optical components will allow manufacturers to produce high-quality, customizable optical components of any geometry quickly and cheaply.
High-speed laser ablation of fused silica. (Images: ©Fraunhofer Institute for Laser Technology ILT, Aachen)
Researchers at the Fraunhofer Institute for Laser Technology (Fraunhofer ILT) used a computer-controlled CO2
laser to heat a quadratic piece of fused silicon to its evaporation temperature (2230°C), carving away at the silicon much as a sculptor would cut away sections of marble to create a statue.
The laser uses custom inputs to control how much silicon it removes and what shape it makes, so that virtually any surface form can be produced. Once the silicon is shaped, it is reheated to near the evaporation point to reduce roughness, and the material will stay polished while it cools. Further imperfections can be buffed out afterward using the same ablative process.
Components after individual steps of the process chain.
As the laser process is controlled by computer data, the inputs can easily be changed to create optical components to order. The new process is also estimated to speed up manufacturing time by a factor of 10, which could drastically drive down the cost of manufacturing and increase production. However, before it can be applied in industry, the technique must be optimized by increasing the precision of the laser ablation and the quality of the polishing process.
The researchers are presenting their process at AKL, the International Laser Technology Congress, on the Fraunhofer ILT campus May 9-11.
For more information, visit: www.ilt.fraunhofer.de