Fast, targeted heating of coatings and surfaces

AT DORTMUND-based LIMO, there is suddenly talk of using a laser source for surface heating which will surely astound even seasoned photonics experts. It involves a special application of the Activation Line 300, the most powerful L3 LIMO Line Laser source.

The Activation Line 300 Laser System from LIMO heat and cool functional layers with thicknesses of just a few hundred nanometers  (LIMO/www.markus-steur.de)

"Imagine that a surface with a functional layer only a few micrometers thin is to be heated to over 1000°C," said Dipl.-Ing. Dirk Hauschild, director of Thin-Film Activation at LIMO Lissotschenko Mikrooptik GmbH in Dortmund. "And think about doing this with a substrate that is already destroyed at 500°C."

But it doesn't stop there – the layers that are to be optimized are often composed of small particles or molecules which lose their desired properties and structural size just a few seconds after the processing temperature has been reached.

This calls for fast and targeted heating and cooling, which can be met with the use of an in-line high-temperature process that provides targeted surface heating in a matter of milliseconds using the Activation Line 300.

With its high electro-optic energy efficiency of over 40%, the most powerful L3 LIMO Line Laser heats even the thinnest functional layers (> 0.1 μm to > 100 μm) with an intensity of 40kW/cm2 in a few milliseconds – delivering outstanding precision and consistency (beam quality M2 < 3 in the processing direction) in the process. Because of the low thermal capacity, the layers also cool down again very quickly.

"The laser energy thus serves to functionalize the layer and, as a result, add to its value," Mr Hauschild explained.

The targeted irradiation using the laser line profile, the user can uniformly temper large surface areas, and enables customized annealing, crystallization and sintering.

"Precision tempering of coatings on glass, metal, ceramics, films and even on paper is also possible," said Mr Hauschild. "For the production process, the user can also utilize extremely small energy and process windows that would otherwise not be feasible with the use of conventional technologies.”

At the LIMO Applications Center in Dortmund, Germany, thin film experts can work with customers to process innovative materials and coating samples to obtain the optimal design and customization of an Activation Line laser source.