High-compact picosecond laser functionalizes surfaces with microscale precision

Despite recent advances in high-powered, ultrashort pulsed lasers, industrial applications that require using intense lasers over large surfaces remain a difficult task. One proposed solution has been to combine multi-spot parallel surface ablation with high-speed techniques. New work provides an experimental example for how such a system could work.

Bruening et al. present the results of a newly developed high-compact picosecond laser that can rapidly functionalize surfaces with high power. Using a diffractive optical element, a 500-watt with high pulse repetition rates was distributed into 8 or 16 parallel beamlets, each controlled by its own acousto-optical modulator.

“The generated spots can be modulated individually, so every spot behaves like a laser of its own,” said author Stephan Bruening. “Through a corresponding software synchronization, it has 8 or 16 parallel independently of each other working tools.”

The group tested their device for its efficacy by creating an embossing roller as a master for various optical, plastic and biological structures. It was able to process features down to 2 µm to several 10 µm in areas of 2 m² on an embossing roller as a master that allows for replication with different capabilities, such as reducing friction, improving soft touch and guiding light elements.

As many functional surfaces require even smaller features, Bruening said the group next hopes to decrease the ablation diameter by way of using shorter wavelengths up to UV light. In addition, they also hope to increase lateral ablation precision by reducing pulse lengths to less than 1 picosecond.

Source: “High-throughput micromachining with ultrashort pulsed lasers and multiple spots,” by Stephan Bruening, Keming Du, Manfred Jarczynski, and Arnold Gillner, Journal of Laser Applications (2019). The article can be accessed at https://doi.org/10.2351/1.5122853 .