The invention relates to the usage of a tunable, resonant electromagnetic field for both, the targeted fabrication of structures with dimensions smaller than the used beam diameter and the targeted fabrication of ultra small particles. Therefore, the electromagnetic field that is created by an ultra short laser pulse on the surface of an object is superposed with an external field to achieve a resonance rise specific to the processed material.

Figure: Setup for resonant surface treatment using a laser and an external field. Via two electrodes which are located on the work piece (left- and right-hand side) of the area to be treated, a tunable electrical field can be applied. This field superposes the electro-magnetic field of the laser making it much easier to reach the material dependent resonance condition. (Source: V. Schütz)

The conventional fabrication of micro- or nano-structured surfaces is of great interest for a huge amount of industrial or R&D applications. Using (ultra) short laser pulses, so called LISOS ("laser induced self organizing structures") can be produced quite easily. Since the process is taking place in close vicinity to the ablation threshold, small laser intensities suffice to fabricate these LISOS. However, to process larger areas the average laser power needs to be increased to several kilowatts. Taking today's state of the art, this results in high acquisition and maintenance costs for the needed laser systems consequently raising the inhibition threshold in industry.

How to solve this problem? Read More at MBM ScienceBridge here