Fig. 1. Propagation of electromagnetic wave varying with the coordinate system^[2]

Fig. 2. Spherical shell invisibility cloak^[2]

Fig. 3. Virtual-real space transformation of optical conformal mapping^[6]. (a) Incidence at a 45° oblique angle; (b) horizontal incidence

Fig. 4. The structure of cylindrical invisibility device^[7]

Fig. 5. Schematic illustration of the carpet invisibility cloak^[8]

Fig. 6. Design of the nonresonant elements and the relation between the unit cell geometry and the effective refractive index^[9]

Fig. 7. Schematic diagram (left) and scanning electron microscopy image (right) of a two-dimensional carpet invisibility cloak in infrared band^[10]

Fig. 8. Experimental results of two-dimensional carpet invisibility cloak in infrared band^[10]. (a) Gaussian beam illumination on a flat surface; (b) Gaussian beam illumination on a curved surface without an invisibility cloak; (c) Gaussian beam illumination on the same curved surface with an invisibility cloak

Fig. 9. Schematic of a 3D carpet invisibility cloak in infrared band^[11]

Fig. 10. Three-dimensional microwave ground-plane invisibility cloak and its refractive index distribution^[12]. (a) Top view of the invisibility cloak; (b) bottom view of the invisibility cloak; (c) side view of the invisibility cloak; (d) the distribution of refractive index in the x-z plane (the material parameters of the whole invisibility cloak are obtained by rotating the x-z plane pattern around the z axis)

Fig. 11. Macroscopic invisibility cloak for visible light^[14]

Fig. 12. Schematic diagram of scattering cancellation^[17]

Fig. 13. Cross-section of a spherical scatterer composed of two concentric layers of different isotropic materials^[17]

Fig. 14. Geometry and scattering efficiency of optical band double-shell invisibility cloak^[20]

Fig. 15. Two-dimensional plasmonic invisibility at microwave frequency^[21]. (a) Object and cloak geometry; (b) numerical simulation of the electric field normal to the cross-section of the uncloaked object at the design frequency; (c) numerical simulation of the electric field of the cloaked object at the design frequency; (d) the model of the experimental setup; (e) the experimental setup

Fig. 16. Three-dimensional plasmonic invisibility cloak^[22]

Fig. 17. Schematic showing mantle invisibility cloak with a specific surface shape^[27]

Fig. 18. Measurement devices for the 3D mantle invisibility cloak^[28]. (a) Far-field measurement device; (b) near-field measurement setup

Fig. 19. Invisibility setup based on the reflection principle^[39]. (a) Invisibility schematic; (b) (c) invisibility experiments; (d) lateral displacement of light rays after they are turned by the mirrors of the cloaking device

Fig. 20. Invisibility setup based on total reflection^[39]

Fig. 21. Invisibility setup based on the refraction principle^[39]. (a) (b) Optical path schematics; (c) (d) experimental devices

Fig. 22. Invisibility schematic based on the lens refraction^[39]

Fig. 23. Schematic and experimental setups of the invisibility system composed of four Fresnel lenses^[39]. (a) (b) Invisibility schematics; (c) (d) invisibility experiments

Fig. 24. Paraxial ray optics invisibility device based on convex lens^[40]

Fig. 25. Principle of the natural light invisibility^[41]

Fig. 26. Illustration of the hexagonal invisibility device in water and air^[41]. (a) (d) Invisibility schematics of the device in water and air; (b)(e) illustrations showing the experimental devices; (c)(f) the experimental results in the both cases, and the dashed lines show the invisible parts of the fish and cat