Ultrafast laser surface functionalization - Applications and pathways to industrialization

Ultrafast laser is a special category of pulsed lasers with their pulse duration in femtosecond and picosecond regimes. If a laser pulse of this kind is focused onto a surface, the peak power can easily reach GW for a fraction of a moment, and the underlying surface can be modified significantly. Specially intended modifications brought by ultrafast laser irradiation can render a surface useful functions that one can benefit in daily life

In this article, we review the interaction of an ultrafast laser pulse with a given surface, and the evolution of the surface after the interaction. At a microscopic scale, this interaction involves interplays of photons, electrons and atoms. This microscale evolution then causes macroscale surface modifications. Applications due to these modifications are introduced in the second part. Since the list of possible applications is endless, only a couple of typical examples are chosen to illustrate the association between ultrafast laser surface modification and surface functionalisation. Applications in energy sector, such as photovoltaics, are explained, due to their technology maturity. Applications in health and care sector are also discussed, due to their increasing demand from our society. Applications in information technology sector, such as data storage and sensing, are also illustrated. With the mechanisms of ultrafast laser surface functionalisation and their applications in mind, the consideration of transferring science into technology is to be given in the last section. Technical issues related to production, and economic issues related to viabilities are all important aspects that engineers have to pay great attention to during the technology transfer process, at the end of which a product readily for use is out of complex laser machine systems.