An invisibility cloak in a diffusive light scattering medium

摘要: Hiding objects with an invisibility cloak appeals to the imagination and also has many practical applications, such as hide unwanted objects, improve stealth techniques extend the range of wireless devices. An can make it seem if object is not there by guiding light around it. Similarly, cloaks from magnetism or heat. In 2014 Schittny et al. presented based on diffusion in a scattering medium. In a medium scattered times due irregularities the medium. Their performed well for all wavelengths throughout visible spectrum. In this research cylindrical rebuilt tested. Furthermore, methods to detect their cloak, i.e. breaking it, are discussed. The design relies theory light. This description of behavior diffuse extensively discussed requirements for perfect cloaking derived analytically. The consist cylinder shell placed a background Perfect obtained by matching diffusivities cloaking shell background result confirmed finite element simulations using COMSOL Multiphysics. For homogeneous illumination, perfect condition results uniform intensity behind 2D case absence absorption in the system reflection at cylinder. 3D simulation resulting intensity was completely uniform, but this possibly caused used mesh size and the height system. In addition, physical experiments have been using homemade cloak. The concentration scatterers varied, leading different diffusivities. The illuminated homogeneously one side (inbound wall). The resulting outbound wall container medium was measured. A clear observed that were close theoretical value cloaking. middle still about 7% lower than background, probably both the white paint itself. The quality determined comparing profile the cloak that obstacle transparent shell. showed a more expected condition. An lies between terms quality. Furthermore, shown ratio background medium wavelength dependent. leads 3% more intensity intended red Also there a refractive index mismatch medium, refraction occur. The photon density then no longer same required perfect cloaking. Both effects promising be exploited