This website uses cookies to ensure a better user experience.
To get more information, please read our Cookie Statement.
Ultrafast Plasmonic Response Ensured by Atomic Scale Confinement
Our colleagues Dino Novko, Marin Petrović, and Marko Kralj, in collaboration with colleagues from Japan (Kyoto University, Toyota Physical and Chemical Research Institute, Open University of Japan), published a paper in the journal ACS Photonics on ultrafast time dynamics of multipole plasmon in heterostructures based on 2D materials.
Ultrafast Plasmonic Response Ensured by Atomic Scale Confinement
Shunsuke Tanaka, Tatsuya Yoshida, Kazuya Watanabe, Yoshiyasu Matsumoto, Tomokazu Yasuike, Dino Novko, Marin Petrović, and Marko Kralj, ACS Photonics 9 (3), 837–845 (2022).
DOI: https://doi.org/10.1021/acsphotonics.1c01454
Our colleagues Marin Petrović and Marko Kralj had investigated a change of optical reflectivity in a special architecture of alkali metal bilayers, and their work was published in 2020 in the journal of Physical Review Letters (http://www.ifs.hr/news/science-news/markoprl2020/). In the special architecture, the previously synthesized epitaxial 2D material was sandwiched between alkali metal layers formed by intercalation and adsorption of alkali atoms. In such systems, a strong absorption band was observed in the visible part of the spectrum originating from the multipole plasmon and its direct binding to external electromagnetic excitation.
In this latest study, expanding collaboration with colleagues from Japan (Kyoto University, Toyota Physical and Chemical Research Institute, Open University of Japan), the time dynamics of this system was investigated. It has been shown that after resonant optical excitation, a transient relaxation of the excited plasmon in the reflectivity spectra occurs in just a few tens of femtoseconds (20-70 fs), cf. Fig. 1. Such behavior is attributed to the localization of a multipole plasmon predominantly within the outer alkali atom layer. For the same reason, strong nonlinearity of the excited system was observed in pump-probe experiments. In addition, the localized excitation non-thermally activates the coherent surface phonons of the system, which is further manifested in the modulation of plasmon relaxation in the THz frequency range (Fig. 2).
These new discoveries show that a multilayer architecture in which 2D materials enable sharp separation, i.e. quantum localization of plasmons within an atomically thin layer, leads to new effects of importance for surface plasmon-polariton systems. New features such as ultra-fast optical response are important for applications in photonics, optoelectronics, and photocatalysis.