Optically switchable mirrors for surface plasmon polaritons propagating on semiconductor surfaces

Using terahertz time-domain spectroscopy measurements, we demonstrate optical switching of the transmission of terahertz surface plasmon polaritons (SPPs) propagating on an indium antimonide surface through Bragg scattering on grooves. The switching of the in-plane transmission of SPPs through the grooves is mediated by the modification of the stop-gap width due to changes of the surface plasmon characteristics, which are induced by the optical generation of charge carriers. The use of a semiconductor surface allows us to achieve switching at extremely low excitation powers. The experimental data can be quantitatively reproduced using rigorous numerical calculations for surfaces with varying dielectric function. Such an optically active device opens further possibilities for low-frequency surface plasmon optics.

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