Fig. 1. Single-photon emission enhancement by metallic micro-nano structures. (a) Metal bowie antenna structure (left) and decay curve of normalized photoluminescence (right) ^[20]; (b) Gold nanorod structure (left) and decay curve of normalized photoluminescence (right) ^[22]; (c) Concentric bullseye structure (left) and decay curve of normalized photoluminescence (right) ^[23]

Fig. 2. Single-photon emission direction manipulated by metallic micro-nano structures. (a) Metal‐dielectric parabolic structure (left) and emission pattern of a single quantum dot (right) ^[28]; (b) Bullseye structure of concentric titania ring (left) and emission pattern of a nanodiamond (right) ^[30]; (c) Asymmetric bullseye structure (left) and schematic diagram of working principle (right) ^[31]

Fig. 3. Single-photon polarization states manipulated by metallic micro-nano structures. (a) Nanocube dimer structure (left) and schematic diagram of polarization properties (right) ^[36]; (b) Metallic nanowire structure placed on a metallic substrate (up) and intensity (|E|²) distribution in the x-y plane (down) ^[37]; (c) Concentric bullseye structure (left) and schematic diagram of polarization properties (right) ^[38]; (d) Scalar-superposition metasurface structure ^[40]; (e) Bifocal metalens structure ^[41]; (f) Anisotropic metasurface structure ^[42]