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.