In the newest issue of Nature, scientists from Institute of Low Temperature and Structure Research, Polish Academy of Sciences (Prof. A. Bednarkiewicz, MSc. A. Kotulska) in cooperation with scientists from the USA (Berkley Lawrence Lab. i Columbia Univ.) and South Korea reported about new colloidal nanomaterials demonstrating photon avalanche (PA) emission. Although, photon avalanche phenomenon has been known in single crystals doped with lanthanides ions since the 80’s  of XX century, the studies presented in current issue of Nature show, for the first time, the possibility of observation of this effect in colloidal nanomaterials. In this process, the luminescence intensity increases very steeply (as avalanche) in response to minute increase of photoexcitation intensity - it resembles the behavior of a transistor or the principle of laser operation, but takes place using photons in the near infrared range.

The first and the biggest achievement of these studies is the demonstration of photon avalanche phenomena in single colloidal avalanche nanocrystals (ANPs). In opposite to conventional lanthanide doped nanoluminophores which suffer from concentration quenching at doping levels higher than 1%, here the energy cross relaxation served as positive feedback with excited state absorption replacing ground state absorption. In consequence, with the ANPs doped with unprecedently high 8% of Tm ions under 1064 nm photoexcitation, each doubling the photoexcitation intensity above the PA threshold leads to 10 000 higher emission intensity. Thanks to this giant nonlinear anti-Stokes luminescence, the researchers demonstrated possibility of simple super-resolution imaging with inherent 70 nm spatial resolution. Unlike to traditional methods of imaging below diffraction limit, instead of spatial structuring of laser excitation (as in STED) or sophisticated signal processing (as in PALM/STORM) the super-resolution images were obtained with conventional confocal microscope in a direct manner.

The obtained results are cutting edge research which not only define new directions in materials science and photo physics of avalanche process at nanoscale, but also may allow for numerous applications such as ultrasensitive biological sensors (of pathogens or molecules, in the cells and tissues), sensors of physical quantities (such as temperature or pressure), neuromorphic computing, construction of mid-infrared photons detection, as new nano-lasers, or as in the original work, fluorescence super-resolution imaging below the light diffraction limit.

The studies involved scientists from Columbia University (USA) (the group of Prof. James Schuck), Lawrence Berkeley National Laboratory (USA) (the group of Prof. Emory Chan and Prof. Burce Cohen), the Institute of Low Temperature and Structural Research of the Polish Academy of Sciences (Poland) (Prof. Artur Bednarkiewicz's group) and the Korea Research Institute of Chemical Technology (South Korea) (Prof. Yung Doug Suh's group).

The research was funded from several sources. In Poland, research was carried out thanks to the financial support from the National Science Center under the OPUS16 Lantavalan grant (2018/3 / B / ST5 / 01827), leaded by prof. dr hab. Eng. Artur Bednarkiewicz from the Institute of Low Temperature and Structural Research of the Polish Academy of Sciences in Wrocław, Poland.


„Giant nonlinear optical responses from photon-avalanching nanoparticles”, C. Lee,  E. Z. Xu, Y. Liu, A. Teitelboim, K. Yao, A. Fernandez-Bravo, A. M. Kotulska, S. H. Nam, Y. D. Suh*, A. Bednarkiewicz*,  B. E. Cohen*, E. M. Chan*, P. J. Schuck*, Nature 589,  230–235 (2021), DOI: