ECI Webinar: "From chiral steering of free-induction decay to highly efficient XUV generation through high-order frequency mixing"

Wednesday the 15th of December 2021 @ 15h00 CET

Speaker: Margarita KHOKHLOVA, Postdoctoral researcher

Max-Born-Institut Berlin, GERMANY

Title of the talk: "From chiral steering of free-induction decay to highly efficient XUV generation through high-order frequency mixing"

Abstract: Chiral discrimination has recently become an emerging frontier in ultrafast physics, with remarkable progress achieved in multiphoton and strong-field regimes. Rydberg excitations, unavoidable in the strong-field regime and intentional for few-photon processes, arise in all these approaches. Here we show how to harness this ubiquitous feature by introducing a new phenomenon, enantiosensitive free-induction decay, steered by a tricolour chiral field at a gentle intensity, structured in space and time. Our theoretical work introduces a general, extremely sensitive, all-optical, enantiosensitive detection technique which avoids strong fields and takes full advantage of recent advances in structuring light. In the second part of my talk, I will present a study of the generation of coherent XUV using intense laser fields in a rapidly ionising gas. We show that the blue shift during propagation is a dominant limitation for the high-harmonic generation efficiency for visible or near-UV drivers. We introduce a new spatial scale, the blue-shift length, which sets the upper bound for its quadratic growth. Moreover, we show that this restriction can be overcome by adding a weak mid-IR field: the phase-matched high-order frequency-mixing process does not suffer from this blue shift, and the generated XUV intensity grows quadratically.