Backward jet propulsion of particles by femtosecond pulses in hollow-core photonic crystal fiber

Abstract

A dielectric microparticle, optically trapped within an air-filled hollow-core photonic crystal fiber (PCF), is accelerated backwards close to the speed of sound when a single guided femtosecond pulse is incident upon it. Acting as a spherical lens, the particle focuses a fraction of the pulse energy onto its inner rear surface, causing the material to ablate. The resulting plasma and vapor jet act like a rocket motor, driving the particle backward at peak accelerations conservatively estimated at more than a million times gravity. Using counter-propagating pulses to suppress particle motion, the effect may permit the inner core walls to be coated locally with different materials, allowing optical devices to be created at otherwise inaccessible points inside long lengths of hollow-core PCF.