The space-time Talbot effect

TL;DR

This paper reports the first observation of a combined space-time Talbot effect in optics, where a special V-wave structure exhibits synchronized revivals due to equal diffraction and dispersion lengths, unifying spatial and temporal self-imaging.

Contribution

It introduces the concept of a space-time Talbot effect and demonstrates it experimentally using a novel V-wave optical field with equal diffraction and dispersion lengths.

Findings

Observation of a unified space-time Talbot effect in optics.

Identification of a V-wave structure with equal diffraction and dispersion lengths.

Revealing a single self-imaging length scale governing the effect.

Abstract

The Talbot effect, epitomized by periodic revivals of a freely evolving periodic field structure, has been observed with waves of diverse physical nature in space and separately in time, whereby diffraction underlies the former and dispersion the latter. To date, a combined spatio-temporal Talbot effect has not been realized in any wave field because diffraction and dispersion are independent physical phenomena, typically unfolding at incommensurable length scales. Here we report the observation of an optical 'space-time' Talbot effect, whereby a spatio-temporal optical lattice structure undergoes periodic revivals after suffering the impact of both diffraction and dispersion. The discovered space-time revivals are governed by a single self-imaging length scale, which encompasses both spatial and temporal degrees of freedom. Key to this effect is the identification of a unique pulsed optical field structure, which we refer to as a V-wave, that is endowed with intrinsically equal diffraction and dispersion lengths in free space, thereby enabling self-imaging to proceed in lockstep in space and time.