Matthew Dale explores the advantages of increasing the average power of ultrafast lasers, and discovers how this higher power can be delivered to the workpiece

Ultrafast lasers are rapidly revolutionising manufacturing. The ultrashort pulses they generate – with durations ranging from femtoseconds to picoseconds – enable the extremely precise micro- and nanofabrication of a wide range of materials, due to their extremely low thermal penetration and the non-linear absorption effects they induce. As described by the Fraunhofer ILT’s Dr Arnold Gillner in our last issue, this has led to these sources being adopted in a wide range of applications – including structuring, drilling, engraving, welding and cutting – across numerous sectors – including displays, automotive, electronics, photovoltaics and medical. Between my visits to AKL last year and

the Laser World of Photonics this year, a clear development trend underway is that the average power of ultrafast lasers is on the rise. At AKL, for example, the Fraunhofer ILT announced its intentions to develop ultrafast lasers with average powers ranging from 5kW to 20kW by 2022. Meanwhile, at the Laser World of Photonics, ultrafast laser manufacturer Amplitude revealed and demonstrated a new 300W femtosecond laser that has been developed within the framework of the TresClean project. Tresclean is one of several EU-funded projects ongoing in which ultrafast lasers with average powers up to the kilowatt range are being developed for a wide range of innovative micro- and nano-structuring applications. According to Dr John Flemmer, however, business development manager at Scanlab, a manufacturer of scanning systems for ultrafast lasers, these increasing average powers will actually be much higher than is needed to perform the majority of applications that ultrafast lasers are currently used for.

24 LASER SYSTEMS EUROPE AUTUMN 2019 ‘We heard from an integrator recently

that for most micromachining ultrafast applications, 10 to 20W is enough,’ he confirmed. ‘So if you are a company looking to buy an ultrafast laser machine, you’d be good to go with this amount of power.’ If this is indeed the case, then why are multiple businesses and projects seeking to increase the average power of ultrafast sources? The answer, as explained by Dr Jose

Antonio Ramos, director of research and development at Lasea, an integrator of ultrafast lasers, is so that the throughput of ultrafast laser processing can be dramatically increased, and so that new applications – currently deemed impractical due to the lack of throughput associated with the technology – can be enabled. ‘One application that this higher

throughput could be of interest for is the structuring of moulds and tools for creating textured plastic surfaces – for example car dashboards,’ he noted. ‘Another application currently in high demand of ultrafast laser technology is the creation of hydrophobic surfaces, however this is still currently unfeasible due to the lack of throughput available for most applications.’ Creating functionalised surfaces such

as those exhibiting hydrophobicity is the current focus of the EU project ‘LAMpAS’ that Lasea is a partner of, which began this year. In addition to developing a 1.5kW picosecond laser with a repetition rate up to 10MHz, the project seeks to combine direct laser interference patterning – creating periodic surface structures using beam interference patterns – with a high-speed polygon scanner to enable the mass-production of functional micro- and nanostructures on a range of surfaces, at a rate of 1 to 5m² per minute. These structures will provide antibacterial and self- cleaning properties, in addition to friction reduction, optical security functions and decorative effects. Combining beam inferencing with high- speed scanning technology is one of two strategies that Ramos explained can be

Scanlab’s five-axis Precsys system can deflect ultrashort pulses in the x,y plane, in addition to being able to tilt them for complex drilling applications



Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48