Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 13: Poster I
HL 13.3: Poster
Monday, March 18, 2024, 15:00–18:00, Poster E
Two-photon excitation channels in CuI — •Andreas Müller1, Leonard Käferstein1, Lukas Trefflich1, Steffen Blaurock2, Harald Krautscheid2, Marius Grundmann1, and Chris Sturm1 — 1Felix-Bloch-Institut für Festkörperphysik, Universität Leipzig, Linnéstr. 5, 04103 Leipzig, Germany — 2Institut für Anorganische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
Having recently identified strong two-photon absorption (2PA) in CuI [1], we’re examining the excitation channels linked to this phenomenon.
We investigate the interferometric autocorrelation (IAC) function of CuI across various excitation energies to discern distinct excitation channels in 2PA-induced photoluminescence (PL). Probing near the 2PA edge (795 nm), the broadening of the IAC function of CuI is similar to the pulse duration of the laser (FWHM ≈ 200 fs) suggesting an excitation assisted by a virtual level. In contrast, probing with 460 nm, a different IAC shape emerges with significant broadening (FWHM ≈ 475 fs). Given the predicted presence of a defect level at this energy [2] and the alignment with the extension of the DAP band in this excitation range, we attribute these alterations to 2PA process assisted by a real level. Similar variations in the IAC function have been documented in prior literature on GaAs [3], which supports our interpretation. We estimate a real-level lifetime of approximately 220 fs.
[1] A. Müller et al., Appl. Phys. Lett. 123, 122103 (2023)
[2] S. Koyasu et al., J. Appl. Phys 125, 115101 (2019)
[3] T. Hattori et al., Jpn. J. Appl. Phys. 39, 4793 (2000)
Keywords: Photoluminescence; Optical autocorrelation; Two-photon absorption; Nonlinear optics; Excitons