Few-Cycle Surface Plasmon Polariton Generation by Rotating Wavefront Pulses

A concept
for the efficient generation of surface plasmon polaritons
(SPPs) with ultrashort duration close to the single-cycle limit is
presented. The scheme is based on grating coupling and laser pulses
with wavefront rotation (WFR), so that the resonance condition for
SPP excitation is satisfied only for a time window shorter than the
driving pulse. The feasibility and robustness of the technique is
investigated by means of simulations with realistic parameters. In
optimal conditions, we find that a 29.5 fs pulse with an 800 nm wavelength
can excite SPPs with <4 fs duration (∼1.5 laser cycles)
and a peak field amplitude ∼2.7 times the peak value for the
laser pulse.