Web Release Date: January 9,
Experimental Observation of an Extremely Dark Material Made By a Low-Density Nanotube Array
and
The Future Chips Constellation & Department of Physics, Applied Physics and Astronomy, and Department of Material Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180
Received September 14, 2007
Revised December 9, 2007
Abstract:
An ideal black material absorbs light perfectly at all angles and over all wavelengths. Here, we show that low-density vertically aligned carbon nanotube arrays can be engineered to have an extremely low index of refraction, as predicted recently by theory [Garcia-Vidal, F. J.; Pitarke, J. M.; Pendry, J. B. Phys. Rev. Lett. 1997, 78, 4289-4292] and, combined with the nanoscale surface roughness of the arrays, can produce a near-perfect optical absorption material. An ultralow diffused reflectance of 1 × 10-7 measured from such arrays is an order-of-magnitude lower compared to commercial low-reflectance standard carbon. The corresponding integrated total reflectance of 0.045% from the nanotube arrays is three times lower than the lowest-ever reported values of optical reflectance from any material, making it the darkest man-made material ever.
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