Fig. 9
From: Spontaneous emission in micro- or nanophotonic structures
The basic concepts and Purcell enhancement of metasurface. a The SEM image of typical metasurface [301]. The schematic diagrams of controlling the (b) phases [302], (c) frequencies [303], and (d) polarizations [304] of electric field by metasurface. e Metasurface controlling the light polarization for anisotropic quantum vacuum [305]. f Anisotropic Purcell factors of x- and y-polarized emitters in the metasurface (e) [305]