04/05/2026
📌📌📣📆SEMINARIUM Z FIZYKI BIOLOGICZNEJ I BIOINFORMATYKI
Instytutu Biochemii i Biofizyki PAN, Instytutu Fizyki PAN i Zakładu Biofizyki UW
📆Wednesday, 06.05.2026, 15:15 (3.15 p.m. CET)
Institute of Physics, Polish Academy of Sciences
Al. Lotników 32/46, 02-668 Warsaw
Auditorium (turn left at the reception desk) and https://zoom.us/j/91976153012?pwd=azNiMWE4UnhPN3lRQlY2UHZHOXVkQT09
📚📚"High dimensional and high resolution NMR methods for studies of intrinsically disordered proteins"
Prof. Wiktor Koźmiński
Biological and Chemical Research Centre
University of Warsaw
Bogdan Lesyng (UW)
Anna Niedźwiecka (IF PAN)
Piotr Zielenkiewicz (IBB)
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Meeting ID: 919 7615 3012
Passcode: 747922
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ABSTRACT
Photon avalanche (PA) is a highly nonlinear optical phenomenon first discovered in
1979, originally investigated in bulk crystals at cryogenic temperatures for mid-infrared photon detection and upconversion lasers. It is initiated when photon absorption triggers a cascade of excited-state absorption (ESA) and energy transferprocesses, forming a positive feedback loop that rapidly amplifies emission. A defining feature of PA is a sharp excitation power threshold, above which the luminescence intensity increases dramatically. Beyond this threshold, the emission intensity (IE) follows a power-law dependence on excitation power (IP), IE=(IP)^S, with an exceptionally large nonlinearity index S exceeding 10 and sometimes reaching several hundred. The process exhibits efficient anti-Stokes emission and a characteristic S-shaped dependence of emission intensity on excitation power density [1]. Achieving PA requires stringent conditions, including resonant ESA between excited states and an ESA cross section much larger than ground-state absorption. Equally critical is efficient cross-relaxation between lanthanide ions, which multiplies the population of intermediate states and sustains the avalanche process. Recent demonstrations of PA in nano- and micro-scale materials, particularly Tm^3+-doped low-phonon hosts, have opened new opportunities for ultrasensitive sensing and advanced photonic technologies. During the talk, the basics of PA will be presented, likewise the novel concepts and demonstrations of superresolution imaging [2,3,4], and ultrasensitize sensing [1,5,6]. Some new directions and challenges will be indicated towards better (lower threshold, controlled non-linearity) PA nano & micro particles and layers.
References
1. M. Szalkowski, A. Kotulska, M. Dudek, Z. Korczak, M. Majak, Ł. Marciniak, M.
Misiak, K. Prorok, A. Skripka, P. J. Schuck, E. M. Chan, A. Bednarkiewicz, et al.,
Chem. Soc. Rev. 54, 983 (2025).
2. Artur Bednarkiewicz, Emory M.-Y. Chan, Agata M. Kotulska, Łukasz Marciniak,
Katarzyna Prorok, et al., Nanoscale Horiz. 4, 706 (2019).
3. Lee, E. Xu, Y. Liu, A. Teitelboim, K. Yao, A. Fernandez-Bravo, A. Kotulska, S.
H. Nam, Y. D. Suh, A. Bednarkiewicz, B. E. Cohen, E. M. Chan, P. J. Schuck, et
al., Nature 592, 554 (2021).
4. S. Karmegam, M. Szalkowski, M. Misiak, K. Prorok, D. Szymański, A.
Bednarkiewicz, et al., arXiv:2507.14667 (2025).
5. Bednarkiewicz, E. M. Chan, K. Prorok, et al., Nanoscale Adv. 2, 4863 (2020).
6. M. Majak, M. Misiak, A. Bednarkiewicz, et al., Mater. Horiz. 11, 4791 (2024).