Exploiting the Momentum Distribution in Atomically Confined Plasmonic Fields by Inelastic Scatterings

• Published in: The journal of physical chemistry letters 2023-01, Vol.14 (2), p.363-369
• Main Authors: Xie, Zhen, Cao, Xin-Rui, Wang, Li, Yu, Hai-Zhen, Wang, Chuan-Kui, Tian, Guangjun, Luo, Yi, Duan, Sai
• Format: Article
• Language: English
• Subjects: Physical Insights into Light Interacting with Matter
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.2c03650

The utilization of atomically confined plasmonic fields has revolutionized the imaging technique. According to the fundamental position–momentum uncertainty principle, such a narrow spatial distribution certainly leads to a broad momentum distribution in the fields, which has however been overlooked. Here we propose a novel exploitation for the momentum distribution by adaptively satisfying the conservation law of momentum in inelastic Raman scatterings in periodic systems, providing a unique optical means of directly measuring the whole phonon dispersions. The proposed technique is particularly useful for measuring phonon dispersions of low-dimensional hydrogen-rich materials, which are completely inaccessible via other techniques. The numerical results for a single all-trans polyacetylene chain demonstrate that all phonon dispersion branches can be conclusively measured from their Raman images for the first time. Our findings highlight a unique advantage of the emerging momentum-based nanophotonics and open the door for exploiting highly confined plasmonic fields in another dimension.