JR Centre for Material processing with ultrashort pulsed lasers

With ultrashort pulsed lasers, almost all materials can be processed with high precision. Research is being carried out here into a fundamental understanding of the laser-matter interaction in various materials - in particular glass and polymers

Material processing using pulsed lasers is state of the art in many areas today, for example in semiconductor technology or Medicine. The bombardment of materials with pulsed laser radiation results in material removal, which is known as ablation. The effect is used for drilling very fine holes, cutting and welding and for removing layers, among other things.

Ultrashort pulsed lasers work with laser pulses in the femto- and picosecond range (10-12 - 10-15s) and have only recently become suitable for industrial applications. Compared to conventional pulsed lasers, ultrashort pulsed lasers have several advantages that lead to high processing precision with almost all materials.

-The mechanisms by which the laser photons are absorbed by the material differ from those of conventional lasers (multiphoton absorption mechanisms), enabling better processing of previously difficult materials such as glass.

-Cold ablation: The removed material transports the energy away so quickly that no significant heating occurs. In conventional applications, heating can lead to cracks in the material.

-Avoidance of scattering losses through temporal decoupling: The material is released after the pulse has hit the material.

Open questions about this technology relate in particular to the details of the reaction of different materials to laser pulses within this special pulse duration range. This is where this centre comes in: Research is being carried out into a fundamental understanding of laser-matter interaction with ultrashort laser pulses. The focus is on materials that are difficult to process with conventional laser sources and on materials that are considered promising for the development of microsystems.

It is important to control and analyse the process parameters. The centre has extensive analytical facilities for this purpose, from sample preparation to electron microscopy.

The findings of the research work are applied to a number of specialised areas: Processing of dielectric materials and polymer materials as well as selective ablation of micro-technical layer systems.

There are many possible areas of application for the research results: Biochips, sensors, microsystems, microfluidics (behaviour of liquids and gases in the smallest of spaces).