Surface plasmon polariton waveguides with subwavelength confinement<xref rid="cpb_27_9_094216fn1" ref-type="fn">*</xref><fn id="cpb_27_9_094216fn1"><label>*</label><p>Project supported by the National Natural Science Foundation of China (Grant Nos. 11704266 and 11774245), the Fok Ying Tung Education Foundation, China (Grant No. 151010), the Scientific Research Base Development Program of Beijing Municipal Commission of Education, China, the General Foundation of Beijing Municipal Commission of Education, China (Grant No. KM201810028006), and the Training Program of the Major Research Plan of Capital Normal University, China.</p></fn>

Surface plasmon polariton waveguides with subwavelength confinement**

Project supported by the National Natural Science Foundation of China (Grant Nos. 11704266 and 11774245), the Fok Ying Tung Education Foundation, China (Grant No. 151010), the Scientific Research Base Development Program of Beijing Municipal Commission of Education, China, the General Foundation of Beijing Municipal Commission of Education, China (Grant No. KM201810028006), and the Training Program of the Major Research Plan of Capital Normal University, China.

Yang Longkun¹, Li Pan¹, Wang Hancong², Li Zhipeng^{1, †}

(color online) (a) The atomic force microscope (AFM) image of a 3-μm-wide and 70-nm-thick silver stripe. (b) Far-field scattered light image of an SPP propagating in the silver stripe. The inset shows the 1/e propagation length. (c) L_SPP in 70-nm-thick silver stripes as a function of stripe width (λ = 633 nm), reproduced from Ref. [49]. (d) Near-field PSTM images of surface plasmons propagating along gold stripes with different widths (λ = 780 nm), reproduced from Ref. [51].