Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 15: 2D Materials 3 (joint session HL/CPP/DS)
HL 15.8: Talk
Tuesday, September 6, 2022, 11:45–12:00, H36
Broadband pump-probe microscopy at 1.5 MHz repetition rate — •Devapriyo Mithun1, Michael Frosz2, and Giancarlo Soavi1 — 1Institute of Solid State Physics, Friedrich Schiller University Jena, Jena, Germany — 2Max Planck Institute for the Science of Light, Erlangen, Germany
Ultrafast pump-probe spectroscopy is one of the most commonly used techniques to resolve photoinduced excited states dynamics: a pump pulse excites the system under investigation, which is then monitored by measuring the changes in the differential reflection (ΔR/R) of a temporally delayed probe pulse. Here, we discuss the realization of a pump-probe setup, which exhibits high sensitivity operating with a temporal resolution of ≈ 100 fs and spatial resolution of ≈ 3 µm with 515 nm pump and a broadband probe spectrum in the range 650-1000 nm, generated with a photonic crystal fiber.
We modulate the pump pulse at 1.5 MHz using an acousto-optic modulator. By doing this, we achieve a sensitivity, defined as the minimum detectable ΔR/R, of 10-7 at 10 ms integration time. Finally, we implemented a Fourier transform based interferometric detection scheme to achieve a fast measurement of ΔR/R over the entire broadband spectrum.
Our pump-probe setup provides a powerful tool for broadband pump-probe microscopy with high sensitivity and high temporal resolution, which is ideal for the study of nanostructures such as carbon nanotubes and layered materials.