Ultrafast optical modulation of graphene plasmons by pump-induced electron heating
IR-neaSCOPE + fs is a unique ready-to-use nanoscale pump-probe system that provides ultrafast nano-FTIR spectroscopy with < 10 nm spatial and < 100 fs temporal resolution . Tip-enhancement provided by s-SNOM boosts the sensitivity and allows for lower pulse energy & MHz repetition rates for gentle time-resolved analysis of 2D materials at the nanoscale .
Nano-FTIR reflectivity carrier density
-1 0 1 2 3 4 5 Pump-probe delay , ps
IR-neaSCOPE + fs reveals ultrafast femtosecond switching in Graphene
Transient near-field response measured by IR-neaSCOPE + fs in exfoliated single- to tri-layer graphene revealed bi-exponential dynamics . The common rapid initial relaxation at the 100 fs time scale is assigned to a cooling of hot carriers via optical phonon excitation . Further picosecond decay depends on the number of layers indicating the relaxation via acoustic phonons . Modeling of the measured data allowed for an extraction of Drude weights and revealed ultrafast tuning of plasmon resonances under 100x weaker illumination vs . metallic nanostructures , indicating superiority of Graphene for next generation electronics .
M . Wagner et al ., Nano Lett . 2014 , 14 , 894 www . attocube . com