Regensburg 2025 – scientific programme
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 14: Poster
KFM 14.25: Poster
Wednesday, March 19, 2025, 17:00–18:30, P1
Interaction of NaYF4:Yb:Er Upconversion Nanoparticles with ultrashort laser pulses — •Leon Siemon1, Felix Sauerwein1, Thibault Mengis1, Leonie Birk2, Eike Wienbeuker2, Markus Haase2, Jacob Piehler2, and Mirco Imlau1 — 1Institute of Physics, Osnabrück University, Germany — 2Dept. of Biology/Chemistry, Osnabrück University
Lanthanide-doped upconversion nanoparticles (ucNP), such as NaYF4:Yb:Er, play a significant role for future all-optical interrogation techniques of cellular systems due to their ability to convert infrared excitation light (980 nm/Yb-absorption) into green/red luminescence (520, 540, 660 nm/Er-emission). The corresponding conversion characteristics and energy transfer mechanisms have been studied extensively under continuous-wave illumination - however, so far, the interaction of ucNPs with ultrashort laser pulses has not been studied. We have adressed this question via diffuse fs-pulse reflectometry [C. Kijatkin et al., Photonics 4 (2017) 11] of NaYF4:Yb:Er nanoparticles (d≈ 18 nm) exposed to 980 nm sub-ps-pulses (τpulse> 40 fs) at peak intensities up to 1014W/m2 and repetition rates down to 50 Hz. We observe severe differences in the intensity dependence, quantum yield and average power density that are attributed to modified population pathways in the energy diagram if the pulse duration falls below the resonant energy transfer time between Yb and Er ions. The impact of our findings for ucNP applications in cellular environments, particularly to reduce laser-induced cell damages, is discussed. Financial support DFG/RTG2900, ’nanomaterials@biomembranes’.
Keywords: Nanoparticles; Lanthanoide; Ultra fast spectroscopy; Upconversion; Ultra short laser pulses