Synthesis and characterization of attosecond light vortices in the extreme ultraviolet

Abstract

Infrared and visible light beams carrying orbital angular momentum (OAM) are currently thoroughly studied for their extremely broad applicative prospects, among which are quantum information, micromachining and diagnostic tools. Here we extend these prospects, presenting a comprehensive study for the synthesis and full characterization of optical vortices carrying OAM in the extreme ultraviolet (XUV) domain. We confirm the upconversion rules of a femtosecond infrared helically phased beam into its high-order harmonics, showing that each harmonic order carries the total number of OAM units absorbed in the process up to very high orders (57). This allows us to synthesize and characterize helically shaped XUV trains of attosecond pulses. To demonstrate a typical use of these new XUV light beams, we show our ability to generate and control, through photoionization, attosecond electron beams carrying OAM. These breakthroughs pave the route for the study of a series of fundamental phenomena and the development of new ultrafast diagnosis tools using either photonic or electronic vortices.

Generation and Applications of Extreme-Ultraviolet Vortices

“…It has been shown that attosecond pulses as short as ∼200 as are possible to be generated with a vortex structure [40], the so-called attosecond helical beams. The structure and properties of helical beams are explored in Ref.…”

“…A recent experiment demonstrated the synthesis and characterization of XUV attosecond helical pulses [40]. In this experiment, the attosecond vortex pulse ionizes the gas target (Neon and Argon), producing electron wavepackets with helical shape.…”

“…Those open new prospects for spectroscopy in the XUV and X-ray regime, such as exciting forbidden-electric-dipole transitions in quantum dots [90], discerning the magnetic sublevels in atoms and clusters [91], inducing charge current loops in fullerenes controlled by the topological charge of the vortex [92], novel dichroism absorption spectroscopy beyond circularly polarized light [93][94][95], and for the production of unconventional skyrmionic defects [96], which are very promising to produce magnetic memory devices at the nanometer scale [97]. The ionization of atoms with attosecond vortex pulses can also have further applications to tailor and manipulate the ionized electron wavepackets, imprinting an helical phase [40]. Those helical electron bursts can be used for spectroscopy and microscopy applications in condensed matter systems [98,99].…”

Attosecond twisted beams from high-order harmonic generation driven by optical vortices

“…Transverse phase-matching is especially relevant in HHG driven by vortex beams due to their involved transverse field structure [35] . If driven by pure vortex beams, the harmonic vortices are generated with a topological charge q = q (q being the harmonic order and the topological charge of the driver) [13,20] , and with similar divergence [13,20,36] . As a consequence, several XUV highly charged harmonic vortices can by synthesized into twisted coherent attosecond beams, i.e., attosecond pulse trains delayed along the azimuthal beam coordinate.…”

Generation of intense femtosecond optical vortex pulses with blazed-phase grating in chirped-pulse amplification system of Ti:sapphire laser

“…More recently, scientists have been attempting to generate multichromatic OVs with high energy and ultrashort temporal profiles [11][12][13][14][15][16][17]. Such an OV pulse exhibits a high peak power, which is the key to inducing nonlinear phenomena such as filamentation [18], supercontinuum [19], and high-harmonic generation [20,21]. Although the light source is important for studying these fascinating phenomena, there have so far been few experimental realizations owing to the lack of accessibility.…”