Femtosecond laser micromachining and rocket propulsion of micro-particles optically trapped in hollow-core photonic crystal fibre

Femtosecond-laser-based micromachining is actively used in a broad range of applications, including photonic device fabrication and cell ablation [1] . Laser ablation of optically trapped particles has been explored as a means of creating particles with defined shapes [2] , [3] . During those experiments it was found that the particles were pushed away from the trapping point by ablation-induced momentum transfer. Dual-beam optical traps in hollow-core photonic crystal fibre (HC-PCF) permit particles to be stably trapped and moved over extended distances along the fibre axis [4] . Here we report fs laser ablation of particles levitated in HC-PCF, uniquely offering a means of coating the (normally inaccessible) core surfaces with thin films of different materials.