Mrejen M, Yadgarov L, Levanon A, Suchowski H
School of Physics and Astronomy, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
Center for Light-Matter Interaction, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
Sci Adv. 2019 Feb 1;5(2):eaat9618. doi: 10.1126/sciadv.aat9618. eCollection 2019 Feb.
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 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 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 showing, at room temperature, ultraslow EP with a group velocity of ~ 0.017. Our imaging method paves the way for in situ ultrafast coherent control and extreme spatiotemporal imaging of condensed matter.
范德瓦尔斯（vdW）材料因其极化激元模式和相关的深亚波长光限制，为强光与物质相互作用提供了一个令人兴奋的平台。诸如WSe之类的半导体vdW材料对于光子和量子集成技术尤为重要，因为它们在室温下能维持可见 - 近红外（VIS - NIR）激子极化激元（EP）模式。在此，我们开发了一种独特的飞秒 - 纳米尺度的时空成像技术，并观测了WSe波导中的EP动力学。我们的方法基于一种新型的超快宽带脉冲内泵浦 - 探测近场成像，能够在室温下直接可视化WSe中EP的形成和传播，展示出群速度约为0.017的超慢EP。我们的成像方法为凝聚态物质的原位超快相干控制和极端时空成像铺平了道路。
