Airy-Bessel wave packets as versatile linear light bullets

The generation of spatiotemporal optical wave packets that are impervious to both dispersion and diffraction has been a fascinating challenge(1). Despite intense research activity, such localized waves, referred to as light bullets, have remained elusive. In nonlinear propagation, three-dimensional light bullets tend to disintegrate as a result of inherent instabilities(2,3). Threedimensional wave packets that propagate linearly have been reported(4-9), but their utility is severely limited by the need to tailor the wave packet precisely to material properties. To overcome these limitations, we explore a new approach based on the one-dimensional Airy wave packet(10). Here, we report the first observation of a class of versatile three-dimensional linear light bullets, which combine Bessel beams in the transverse plane with temporal Airy pulses. Their evolution does not depend critically on the material in which they propagate, and the consequent versatility will facilitate their study and applications ranging from bioimaging(11) to plasma physics(12).