Time- and angle-resolved photoemission spectroscopy using ultrafast XUV source at around 20 eV

ORAL

Abstract

Time- and angle-resolved photoemission spectroscopy (trARPES) has several advantages over conventional static ARPES measurements. Using trARPES, one can measure electronic states above the Fermi level, track femtosecond or picosecond dynamics in materials, and study transient laser-dressed band structures. We have developed a trARPES setup using high-order harmonic probe pulses produced using a commercial turn-key Yb:KGW laser. The laser, which emits 1030 nm, 290 fs laser pulses with average power of 20 W and tunable repetition rate between 50-200 kHz, is frequency-doubled using a BBO crystal, and focused into a krypton-filled gas cell to generate high-order harmonics. We eliminate low-order harmonic using an aluminum foil filter and optimize the harmonic cutoff using the laser intensity, thereby isolating the 9th harmonic at 21.7 eV. The 9th harmonic probe will be combined with a portion of the 1030 nm laser with a variable time delay for pump-probe experiments. Here, we will present the full characterization of the harmonic light source, as well as first time-resolved measurements in topological materials.

*This work is supported by the Air Force Office of Scientific Research under Award No. FA9550-17-1-0415 and the startup fund from UCF (M.N.).

–

Presenters

  • Yangyang Liu

    • Physics, University of Central Florida

Authors

  • Yangyang Liu

    • Physics, University of Central Florida

  • John Beetar

    • Physics, University of Central Florida

  • Md Mofazzel Hosen

    • University of Central Florida
    • Physics, University of Central Florida, Orlando, Florida 32816, USA
    • Physics, University of Central Florida

  • Gyanendra Dhakal

    • University of Central Florida
    • Physics, University of Central Florida, Orlando, Florida 32816, USA
    • Physics, University of Central Florida

  • Christopher Sims

    • Physics, University of Central Florida

  • Firoza Kabir

    • University of Central Florida
    • Physics, University of Central Florida, Orlando, Florida 32816, USA
    • Physics, University of Central Florida

  • Klauss Dimitri

    • University of Central Florida
    • Physics, University of Central Florida, Orlando, Florida 32816, USA
    • Physics, University of Central Florida

  • Sabin Regmi

    • University of Central Florida
    • Physics, University of Central Florida

  • Michael Chini

    • Physics, University of Central Florida

  • Madhab Neupane

    • University of Central Florida
    • Physics, University of Central Florida, Orlando, Florida 32816, USA
    • Physics, University of Central Florida