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 transfer
processes, 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).

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