In photonics, a meta-waveguide is a physical structures that guides electromagnetic waves with engineered functional subwavelength structures. [1] Meta-waveguides are the result of combining the fields of metamaterials and metasurfaces into integrated optics. [2] [3] The design of the subwavelength architecture allows exotic waveguiding phenomena to be explored. [3] [4]
Meta-waveguides can be classified by waveguide platforms or by design methods. [2] If classified by underlying waveguide platform, engineered subwavelength structures can be classified in combination with dielectric waveguides, optical fibers, or plasmonic waveguides. If classified by design methods, meta-waveguides can be classified as either using design primarily by physical intuition, or by computer algorithm based inverse design methods. [1] [5]
Meta-waveguides can provide new degrees of design freedom to the available structural library for optical waveguides in integrated photonics. [1] [3] Advantages can include enhancing the performance of conventional waveguide based integrated optical devices and creating novel device functionalities. [1] [3] Applications of meta-waveguides include beam/polarization splitting, [3] integrated waveguide mode converters, [4] versatile waveguide couplers, [6] lab-on-fiber sensing, [7] nano-optic endoscope imaging, [8] on-chip wavefront shaping, [9] structured-light generations, [10] and optical neural networks. [11] [12] The meta-structures can also be further integrated with van der Waals materials to add more functionalities and reconfigurability. [13] [14]