Ultrafast spatiotemporal control of surface plasmon polariton launch in orthogonal directions via a compact nanoantenna using chirped laser pulses.

Actively manipulating the directional launch of ultrafast spatiotemporal surface plasmon polariton (SPP) is critical for advancing optical communication and information processing in nanoplasmonic devices. This study introduces an innovative compact nanostructure designed for spatiotemporal control of SPP emission at nano-femto scales. The device is capable of launching SPPs unidirectionally into distinct vertical and horizontal output channels, depending on the wavelength and polarization characteristics of the incident light. We model a solution for the spatiotemporal ultrafast switching of the SPP launch in orthogonal directions on the femtosecond time scale through a compact nanoantenna structure excited by the chirped laser pulses. Additionally, the SPP switching time within the nanoantenna structure is demonstrated to be tunable by adjusting the duration of the incident laser pulse. This work provides a foundation for developing advanced, highly integrated nanophotonic devices and miniaturized high-speed signal processing systems, offering versatile applications in advanced optical nanocircuits.