Superluminal motion

Quantum mechanics

Linguistics

Philosophy

Group velocity

Computational physics

Wavelength

Classical mechanics

Wave packet

Free space

Physics

Optics

Speed of light (cellular automaton)

Acceleration

Space (punctuation)

Physical Review Letters

Although a plethora of techniques are now available for controlling the group velocity of an optical wave packet, there are very few options for creating accelerating or decelerating wave packets whose group velocity varies controllably along the propagation axis. Here we show that "space-time" wave packets in which each wavelength is associated with a prescribed spatial bandwidth enable the realization of optical acceleration and deceleration in free space. Endowing the field with precise spatiotemporal structure leads to group-velocity changes as high as ∼c observed over a distance of ∼20 mm in free space, which represents a boost of at least ∼4 orders of magnitude over X waves and Airy pulses. The acceleration implemented is, in principle, independent of the initial group velocity, and we have verified this effect in both the subluminal and superluminal regimes.Received 1 April 2020Accepted 30 October 2020DOI:https://doi.org/10.1103/PhysRevLett.125.233901© 2020 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasClassical opticsLasersOptics & lasersAtomic, Molecular & Optical

Accelerating and Decelerating Space-Time Optical Wave Packets in Free Space