“…With the development of nanotechnology, new opportunities have opened up for the integration of artificially engineered subwavelength materials with enhanced properties not otherwise found in nature, so-called metamaterials [ 8 , 9 , 10 ], with photonic waveguides. Among the different structures integrated to waveguides for signal filtering that can be mentioned are dielectric and plasmonic ring resonators [ 11 , 12 ], gratings [ 13 , 14 , 15 ], nanodisk [ 16 , 17 , 18 ] and asymmetric resonators [ 19 , 20 ], nanostructured plasmonic waveguides [ 21 , 22 ], waveguide cladding modulators [ 23 , 24 , 25 , 26 ], and photonic crystals [ 27 , 28 ]. In a previous work, we experimentally demonstrated that a gold nanoslab placed on top of an ion-exchanged glass waveguide serves as a stop-band filter of light for a broad bandwidth at near infrared wavelengths [ 29 ].…”