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Proceedings Paper

Reflectance measurements for black absorbers made of vertically aligned carbon nanotubes
Author(s): X. J. Wang; O. S. Adewuyi; L. P. Wang; B. A. Cola; Z. M. Zhang
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Paper Abstract

Black coatings have important applications in space-borne infrared systems, absolute radiometers, and radiometric temperature measurements. Recently, researchers have demonstrated close-to-unity absorptance, with diffuse reflection, by using vertically aligned carbon nanotube (VACNT) arrays. The present study deals with the optical properties of highly absorbing VACNT arrays, with surface features from diffuse to specular. Three CNT arrays were fabricated using a thermal chemical vapor deposition (CVD) technique with different growth conditions to produce highly aligned multi-walled CNT arrays. The bidirectional reflectance distribution functions (BRDFs) were measured with a laser scatterometer at a wavelength of 635 nm. Sharp specular peaks can be seen from the BRDF plots for the relatively smooth sample; while for the relatively diffuse samples, the specular peaks are significantly lower. The directional-hemispherical reflectance (DHR) at wavelengths from 400 to 1000 nm was measured with an integrating sphere and a monochromator. Based on Kirchhoff's law, the absorptance was obtained from the DHR to be between 99.5% and 99.9% for all samples in the measured spectral region.

Paper Details

Date Published: 2 September 2010
PDF: 9 pages
Proc. SPIE 7792, Reflection, Scattering, and Diffraction from Surfaces II, 77920R (2 September 2010); doi: 10.1117/12.861741
Show Author Affiliations
X. J. Wang, Georgia Institute of Technology (United States)
O. S. Adewuyi, Georgia Institute of Technology (United States)
L. P. Wang, Georgia Institute of Technology (United States)
B. A. Cola, Georgia Institute of Technology (United States)
Z. M. Zhang, Georgia Institute of Technology (United States)


Published in SPIE Proceedings Vol. 7792:
Reflection, Scattering, and Diffraction from Surfaces II
Zu-Han Gu; Leonard M. Hanssen, Editor(s)

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