Laser-Induced Damage in Silica Nanofibers in Air and Immersed in Different Liquids in the Nanosecond Regime

Thanks to their unique optical properties, silica nanofibers are used in a growing number of applications. Moreover, the possibility of immerging them in various media adds another interesting feature to these devices. However, as for all optical components, nanofibers are limited by the optical damage that can be induced by a laser. In this Letter, we present for the first time to our knowledge Laser-Induced Damage Threshold (LIDT) measurements of silica nanofibers in air and in three common liquids (ethanol, isopropanol, and water). The experiments were performed in the nanosecond regime with a pump source emitting at the wavelength of 532 nm. Different nanofiber radii (from 220 nm to 450 nm) and two nanofiber lengths (2 cm and 8 cm) were tested. We firstly present the experimental setup and protocol. A significant number of samples were realized, and the results were highly repeatable. We also showed that immerging a nanofiber in a liquid substantially enhanced the LIDT, the most important increase having been obtained for nanofibers immersed in water for which the LIDT energy was almost multiplied by a factor of 2 compared with air ( 0.38 μJ in air vs 0.71 μJ in water for a radius of 350 nm). This property offers a new degree of freedom to widen the field of applications of nanofibers, where high peak powers are needed.