Title: Photoluminescence from metals – theory and experiments
When: Monday, May 19, 2025, 12:00
Place: Department of Theoretical Condensed Matter Physics, Faculty of Sciences, Module 5, Seminar Room (5th Floor)
Speaker: Yonatan Sivan, Ben Gurion University of the Negev
Countless previous experimental works of the light emission (aka photoluminescence) from metals from the last 50 years revealed disagreements on a long series of fundamental aspects [1]. These were not accompanied by a complete theory because the poor understanding of the hard-to-calculate electron non-equilibrium distribution under illumination, as well as the absence of a description of the uncorrelated emissions from a macroscopic object. In my talk, I will provide a simple quantitative theory for this problem. Specifically, based on knowledge of the non-equilibrium electron distribution in illuminated metals [2], we computed in [3] the local emission spectra from an excited metal illuminated by CW and pulsed illumination. This explained the complex dependence of the metal emission on the electric field and resolved arguments associated with the emission statistics, showing when it a non-thermal (“hot”) electron effect, and when it is transformed to thermal emission from a body whose temperature varies in time. Then, using the extension of the Fluctuation-Dissipation Theorem to non-equilibrium electron systems [4], we describe the overall (rather than local) emission from metal structures and demonstrate a good match to a range of measurements. Remarkably, our simple one-line theory shows an excellent match to the lengthy fully rigorous discrete k-space quantum mechanical calculation of the emission described in [5]. Our approach thus provides a simple way to determine the PL from complex nanostructures, and establishes a trivial link to the huge body of literature on thermal emission engineering.
References:
- G. Baffou, ACS Nano 15, 5785−5792 (2021).
- Y. Dubi, Y. Sivan, Light: Science & Applications 8, 89 (2019). I.W. Un, Y. Dubi, Y. Sivan, Faraday Discussion (2019).
- Y. Sivan, Y. Dubi, ACS Nano 15, 8724 (2021).
- A. Pelous-Loirette and J. J. Greffet, ACS Nano 18, 31823–31833 (2024).
- A. R. Bowman, A. Rodríguez Echarri, F. Kiani, F. Iyikanat, T. V. Tsoulos, J. D. Cox, R. Sundararaman, F. J. García de Abajo and G. Tagliabue, Light: Science & Applications 13 (2024).
