Nanosecond laser-induced breakdown assisted by femtosecond laser pre-ionization in air: the effect on spatial resolution and continuous radiationBo Li, Xiaofeng Li, Zhifeng Zhu and Qiang GaoEur. Phys. J. Appl. Phys., 92 2 (2020) 20701DOI: https://doi.org/10.1051/epjap/2020200258