Recently, slot waveguides have also been widely used due to the advantages of breaking through the diffraction limit and confining light to sub-wavelength low-refractive index layers due to the particularity of its structure[9-11]
Recently, slot waveguides have been widely used due to their unique structure, which can break through the diffraction limit and limit the propagation of light in sub wavelength low refractive index layers [9-11]
Recently, groove waveguide has been widely used because it can break through the diffraction limit and limit the propagation of light in the sub-wavelength low refractive index layer by using the particularity of its structure [9-11].