Overcoming the barrier of nanoparticle production by femtosecond laser ablation in liquids using simultaneous spatial and temporal focusing

There exists an increasing demand of industrial-scale production of high-purity ligand-free nanopartides due to the continuous development of biomedicine, catalysis, and energy applications. In this contribution, a simultaneous spatial and temporal focusing (SSTF) setup is first proposed for increasing nanopartide productivity of the eco-friendly pulsed laser ablation in liquids (PLAL) technique. In spite of the fact that femtosecond pulses have proved to achieve higher ablation rates in air than picosecond pulses, in PLAL this is reversed due to the nonlinear energy losses in the liquid. However, thanks to the incorporation of SSTF, the energy delivered to the target is increased up to 70%, which leads to a nanopartide production increase of a 2.4 factor. This breaks a barrier toward the employment of femtosecond lasers in high-efficiency PLAL. (C) 2019 Chinese Laser Press