Transient exciton-polariton dynamics in WSe<sub>2</sub> by ultrafast near-field imaging.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30746484.
- Also identified by DOI 10.1126/sciadv.aat9618 and PMC identifier 6358311.
- Licence recorded as CC BY-NC.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Van der Waals (vdW) materials offer an exciting platform for strong light-matter interaction enabled by their polaritonic modes and the associated deep subwavelength light confinement. Semiconductor vdW materials such as WSe<sub>2</sub> are of particular interest for photonic and quantum integrated technologies because they sustain visible-near-infrared (VIS-NIR) exciton-polariton (EP) modes at room temperature. Here, we develop a unique spatiotemporal imaging technique at the femtosecond-nanometric scale and observe the EP dynamics in WSe<sub>2</sub> waveguides. Our method, based on a novel ultrafast broadband intrapulse pump-probe near-field imaging, allows direct visualization of EP formation and propagation in WSe<sub>2</sub> showing, at room temperature, ultraslow EP with a group velocity of <i>v</i> <sub>g</sub> ~ 0.017<i>c</i>. Our imaging method paves the way for in situ ultrafast coherent control and extreme spatiotemporal imaging of condensed matter.