title: Photonic jet subwavelength etching using a shaped optical fiber tip.
abstract: We demonstrate that photonic jets (PJs) can be obtained in the vicinity of a shaped optical fiber and that they can be used to achieve subwavelength etchings. Only 10% of the power of a 30 W, 100 ns, near-infrared (1064 nm) Nd:YAG laser, commonly used for industrial laser processing, has been required. Etchings on a silicon wafer with a lateral feature size close to half-laser wavelength have been achieved using a shaped-tip optical fiber. This breakthrough has been carried out in ambient air by using a multimode 100/140 μm silica fiber with a shaped tip that generates a concentrated beam at their vicinity, a phenomenon referred to as a PJ, obtained for the first time without using microspheres. PJ achieved with a fiber tip, easier to manipulate, opens far-reaching benefits for all PJ applications. The roles of parameters such as laser fluence, tip shape, and mode excitation are discussed. A good correlation has been observed between the computed PJ intensity distribution and the etched marks' sizes.
authors.forename: Julien
authors.initials: J
authors.lastname: Zelgowski
authors.forename: Andri
authors.initials: A
authors.lastname: Abdurrochman
authors.forename: Frederic
authors.initials: F
authors.lastname: Mermet
authors.forename: Pierre
authors.initials: P
authors.lastname: Pfeiffer
authors.forename: Joël
authors.initials: J
authors.lastname: Fontaine
authors.forename: Sylvain
authors.initials: S
authors.lastname: Lecler