In a new publication from Opto-Electronic Advances; DOI 10.29026/oea.2021.210066, researchers from Shanghai Jiao Tong University, China, Sun Yat-sen University, China and RIKEN Center for Advanced Photonics, Japan, discuss liquid vortexes and flows induced by femtosecond laser ablation in liquid governing formation of circular and crisscross LIPSS.
Since the discovery of laser-induced periodic surface structures (LIPSS) in 1965, one-step LIPSS formation has been regarded as one of distinct advantages of laser micro/nanomanufacturing over 50 years. LIPSS can be formed in diverse materials including metals, semiconductors, ceramics, dielectrics, and polymers with relevant applications in optics, optoelectronics, electrochemistry, biology, and other fields. LIPSS can be categorized into low spatial frequency LIPSS (LSFL), high spatial frequency LIPSS (HSFL), ultrahigh spatial frequency LIPSS (UHSFL) and suprawavelength periodic surface structure (SWPSS) according to their periods relative to laser wavelength. UHSFL is defined as the periodic structure with a period less than 100 nm; HSFL, ~100 nm to less than 1/2 of laser wavelength; LSFL, larger than 1/2 to the same dimension of laser wavelength, while the period of SWPSS is larger than the laser wavelength. For a linearly polarized laser, the direction of LIPSS is typically perpendicular to the direction of laser polarization. Controlling the orientations of LIPSS presents different rainbow colors at the same viewing angle, enabling color printing to be used for anti-counterfeiting applications. Other kinds of LIPSS including triangular, rhombic, arc and circular LIPSS have also been produced using non-linearly polarized light, such as circular polarized or vortex light.
Article reference: Zhang DS, Li XZ, Fu Y, Yao QH, Li ZG et al. Liquid vortexes and flows induced by femtosecond laser ablation in liquid governing formation of circular and crisscross LIPSS. Opto-Electron Adv 5, 210066 (2022) . doi: 10.29026/oea.2021.210066
Keywords: circular LIPSS / crisscross LIPSS / laser ablation in liquid / femtosecond laser ablation in water / liquid vortex / vortex shedding
