Femtosecond polariton interferometry of transient exciton-polaritons in WSe 2 with near-IR probe
neaSCOPE + fs is purposely designed to provide high interferometric stability for pump-probe at NIR and visible frequencies . Reflective optics and integrated delays enable investigations of exciton-polariton dynamics in TMDs at the relevant time & energy scales by easy integration of custom light sources .
s-SNOM reflectivity Reflectivity line profile
Delay time , fs
Position , ยต m
neaSCOPE + fs equipped with custom ultrafast visible pump (~ 650 nm ) and near-IR probe ( 760 nm ) illumination captured the transient formation & propagation of exciton-polaritons ( EPs ) in WSe 2 down to single monolayer in thickness . Analysis of position vs . time profile ( right ) revealed a remarkably slow polariton group velocity ~ 0.017c attributed to a strong Coulomb interaction in the thin transition metal dichalcogenide ( TMD ) and an increased damping due to collision with photoinjected electrons . Understanding the spatiotemporal evolution of EPs in TMDs paves the way for the utilization of slow light phenomena in optical memory , processing and sensing .
M . Mrejen et al ., Sci . Adv . 2019 , 5 , 2 neaSCOPE enables in-situ ultrafast coherent control of TMD systems at the nanoscale mk