Uncloaking Diffusive-Light Invisibility Cloaks by Speckle Analysis


Within the range of validity of the stationary diffusion equation, an ideal diffusive-light invisibility cloak can make an arbitrary macroscopic object hidden inside of the cloak indistinguishable from the surroundings for all colors, polarizations, and directions of incident visible light. However, the diffusion equation for light is an approximation which becomes exact only in the limit of small coherence length. Thus, one expects that the cloak can be revealed by illumination with coherent light. The experiments presented here show that the cloaks are robust in the limit of large coherence length but can be revealed by analysis of the speckle patterns under illumination with partially coherent light. Experiments on cylindrical core-shell cloaks and corresponding theory are in good agreement.



Research Center/Lab(s)

Center for High Performance Computing Research


Deutsche Forschungsgemeinschaft (DFG) (DFG-SPP 1839 “Tailored Disorder”); Helmholtz-Gemeinschaft (HGF); Science and Technology of Nanosystems; Karlsruhe School of Optics and Photonics (KSOP); National Science Foundation (NSF) (DMR-1205223).

Keywords and Phrases

Coherent light; Light; Partial differential equations; Speckle, Coherence lengths; Cylindrical cores; Diffusion equations; Macroscopic objects; Partially coherent light; Speckle patterns; Stationary diffusion; Visible light, Invisibility cloaks

International Standard Serial Number (ISSN)

0146-9592; 1539-4794

Document Type

Article - Journal

Document Version


File Type





© 2017 Optical Society of America (OSA), All rights reserved.

Publication Date

01 May 2017