We demonstrate broadband, near perfect absorption with a conformal coating of a multi-walled carbon nanotube (CNT) forest on an arbitrarily shaped surface. The complex refractive index of such a CNT forest is retrieved from the measured transmission and reflection spectra using Kramers-Kronig constrained variational analysis, which gives a typical value of neff = 1.04 + 0.01i at visible wavelengths. Therefore, when used as a conformal coating on an object, a thick layer of the CNT forest can provide an excellent impedance match to air and near perfect absorption, preventing any detectable light reflection and scattering from the object.
Low density carbon nanotube forest as an index-matched and near perfect absorption coating
Haofei Shi, Jong G. Ok, Hyoung Won Baac, L. Jay Guo; Low density carbon nanotube forest as an index-matched and near perfect absorption coating. Appl. Phys. Lett. 21 November 2011; 99 (21): 211103. https://doi.org/10.1063/1.3663873
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