Freiburg 2024 – scientific programme
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A: Fachverband Atomphysik
A 10: Interaction with Strong or Short Laser Pulses I (joint session A/MO)
A 10.2: Talk
Tuesday, March 12, 2024, 11:30–11:45, HS 1010
Intra-cavity photoelectron tomography and pulsed standing waves at 100 MHz repetition rate — •Jan-Hendrik Oelmann, Tobias Heldt, Lennart Guth, Nick Lackmann, Lukas Matt, Thomas Pfeifer, and José R. Crespo López-Urrutia — Max-Planck-Institut für Kernphysik, Heidelberg, Germany
To get access to multiphoton ionization studies at high laser intensities (∼ 1013 W/cm2) while maintaining the high 100 MHz repetition rate of the driving frequency comb, we have recently developed a novel polarization-insensitive enhancement cavity with an integrated velocity-map imaging (VMI) spectrometer [1, 2]. Polarization-controlled pulse pairs with a variable time delay allow pump-probe experiments. With this polarization control but in single-pulse operation, we were able to tomographically reconstruct 3D photoelectron angular distributions [3] from xenon MPI at 100 MHz repetition rate, revealing resonant Rydberg states during ionization.
Now, we use counter-propagating pulses colliding at the focus to generate intense femtosecond standing waves in the cavity. We probe the phase of these at the nanometer scale using photoemission from a tungsten nanotip. Colliding pulses offer the dual advantage of enabling Doppler-free excitation schemes and of reducing the interaction volume at the focus.
[1] J.-H. Oelmann et al., Rev. Sci. Instrum., 93(12), 123303 (2022). [2] J. Nauta et al., Opt. Lett. 45(8), 2156 (2020). [3] M. Wollenhaupt et al., Appl. Phys. B 95(4), 647-651 (2009).
Keywords: Multiphoton Ionization; Velocity-Map Imaging; Enhancement Cavity; Tomography; Standing Wave