Direct spatiotemporal measurements of accelerating ultrashort Bessel-type light bullets

Abstract

We measure the spatiotemporal field of ultrashort pulses with complex spatiotemporal profiles using the linear-optical, interferometric pulse-measurement technique SEA TADPOLE. Accelerating and decelerating ultrashort, localized, nonspreading Bessel-X wavepackets were generated from a approximately 27 fs duration Ti:Sapphire oscillator pulse using a combination of an axicon and a convex or concave lens. The wavefields are measured with approximately 5 microm spatial and approximately 15 fs temporal resolutions. Our experimental results are in good agreement with theoretical calculations and numerical simulations.

Time-and-space-domain study of diffracting and non-diffracting light pulses

“…All these results were published in [19], and here we restrict ourselves to the decelerating pulse case only.…”

“…Secondly, we touch briefly on our spatiotemporal measurements of accelerating and decelerating Bessel pulses [19]. The term was proposed in [20] where the generation and properties of such pulses were theoretically investigated.…”

Directly recording diffraction phenomena in the time domain

“…Also similar to the Bessel-X pulse the boundary wave pulse has a letter X-like axial cross-section and propagates on the optical axis superluminally. But while the group velocity of the former has a constant value exceeding c, the central spot of the boundary wave pulse is decelerating (see also [1,[9][10][11]). The elementary boundary diffraction waves emanating from the edges of the aperture must travel a longer distance to reach the optical axis compared to the centre of the direct pulse and thus lag behind.…”

Image formation of radially and temporally truncated Bessel beams

“…(3)) than the boundary waves. The X-shaped cross-section of the converging geometrical wavesa so-called Bessel pulse [9] that is most clearly depicted on Fig. 3 parts 4 and 5 -and its central maximum's accelerating motion have already been directly recorded [9] using a novel technique called SEA TADPOLE [10].…”