Fig. 3: Hyperbolic polariton cloaking.

a Illustration of the crystallographic orientation of α-MoO₃ microribbons used in the cloaking device and tailored from the same film. b Optical image of a polaritonic cloaking device composed of four microribbons with β = 45° (ribbons 1 and 3) and β = 135° (2 and 4). The thicknesses of the bottom film and four top ribbons are t₀ = 207 nm and t₁ = 143 nm, respectively. The green dot is a graphite disk (50 nm thickness, 1 μm diameter), which serves as a cloaked defect. c Experimentally measured near-field amplitude images from the device in (b) at an illumination frequency of 900 cm⁻¹. The incident hyperbolic wave undergoes splitting and subsequent recombination, thus realizing in-plane cloaking of the graphite defect. Red-dashed arrows indicate the polariton propagation direction dictated by the Poynting vector, as obtained from the IFCs analysis presented on both sides of the experimental image. The calculated IFCs for each region in the device are shown as blue curves in the left and right parts, with scale bars indicating 20 k₀. d Measured near-field profiles of the cloaking device with (red) and without (blue) the defect placed in the hidden region (blue shaded area). The green shaded area depicts the near-field intensity of the defect. The data is extracted along the red and blue dashed vertical lines in Supplementary Fig. 11. e Close-up view of near-field profiles in (d). Gray vertical dashed lines represent the position of each peak of the near-field profiles. f Simulated near-field (Re{E_Z}) image illustrating the cloaking performance. The red-dashed circle marks the location of the defect in correspondence with the experimental structure. Scale bars in (b, c, f) indicate 3 μm.