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) Photograph of the corrugated metal strip fabricated using a flexible copper clad laminate. (b) Dispersion curves of the spoof SPPs in the corrugated metal strips with different thicknesses (t). The black curve describes the light in free space, reproduced from Ref. [72]. (c) Configuration of the CPWs-to-spoof SPPs converter. I: CPW section. II: Matching transition bridge consisting of gradient grooves and a flaring ground. III: Spoof SPP waveguide (ultrathin corrugated metallic strip). (d) Dispersion curves of the ultrathin corrugated metallic strip (t = 18 μm) with different groove depths (h). The black curve describes the light in free space, reproduced from Ref. [74].