LAMP-SEMINAR

ATTOSECOND METROLOGY AT A SEEDED FREE-ELECTRON LASER

Speaker: PRAVEEN KUMAR MAROJU (Atomic Physics division, Lund University)

Date and time
Venue
Library Block Lecture Hall

Abstract

Electron dynamics on atomic and molecular scales unfold over timescales ranging from a few attoseconds (1 attosecond = 10⁻¹⁸ s) to a few femtoseconds (1 femtosecond = 10⁻¹⁵ s). Probing and controlling such ultrafast phenomena requires light pulses of comparable duration. Over the past three decades, attosecond science has revolutionized our ability to study electron motion in atoms, molecules, liquids, and solids with unprecedented temporal resolution. In recognition of this breakthrough, the 2023 Nobel Prize in Physics was awarded to Pierre Agostini, Ferenc Krausz, and Anne L’Huillier “for experimental methods that generate attosecond pulses of light for the study of electron dynamics in matter”. Much of this progress has been driven by high-order harmonic generation (HHG), a tabletop technique for producing attosecond pulses with central frequencies in the extreme ultraviolet (XUV) spectral region [1,2].  In this talk, I will present the generation of attosecond pulses using a complementary source: free-electron lasers (FELs). FELs offer tunable, high-brightness radiation spanning XUV to hard X-rays [3-6]. I will share results from the seeded FEL FERMI in Trieste, Italy, where we demonstrated the generation of attosecond pulse trains (APTs), along with independent amplitude and phase control, enabling complex attosecond waveform synthesis [6]. Traditional cross-correlation techniques used in the attosecond community, which require sub-femtosecond delay precision, are challenging to implement at FEL facilities. Therefore, we employ a shot-to-shot correlation analysis to characterize the generated APTs. Together with a novel attosecond timing tool demonstrated in our experiments, these results position seeded FELs as complementary source of APTs well-suited for carrying out attosecond time-resolved pump-probe experiments [7].

References

  1. McPherson, A. et al, J. Opt. Soc. Am. B 4, 595 (1987)
  2. Ferray, M. et al., J. Phys. B At. Mol. Opt. Phys 21, L31 (1988)
  3. Ackermann, W. et al., Nat. Photon. 1, 336 (2007), Allaria, E. et al., Nat. Photon. 6, 699 (2012)
  4. Emma, P. et al., Nat. Photon. 4, 641 (2010), Marinelli, A. et al., Appl. Phys. Lett. 111, 151101 (2017)
  5. Duris, J. et al., Nat. Photon. 14, 30 (2020)
  6. Maroju, P.K. et al., Nature 578, 386 (2020)
  7. Maroju, P.K. et al., Nat. Photon. 17, 200 (2023)