Fig. 2: High-quality factor and long-distance propagation of suspended GPs.
From: Active control of micrometer plasmon propagation in suspended graphene

a, b Measured near-field amplitude images of SiO2-supported graphene (a) and suspended graphene (suspension height ~450 nm) (b) near the edge (white dashed line) for different graphene Fermi energies and fixed illumination wavelength λ0 = 10.87 μm (920 cm−1). The scale bar indicates 3 μm. c Quality factor Q (left axis) and propagation length LSPP (right axis) of suspended (maroon curves) and SiO2-supported (orange curves) GPs as a function of Fermi energy. Symbols are obtained from experimental data, while curves are a guide to the eye. Error bars indicate 95% confidence intervals.