Wideband perfect absorption in arrays of tilted carbon nanotubes

In this paper we discuss an interesting property of arrays of metallic carbon nanotubes, namely, the capability of perfect absorption in optically ultrathin layers. The carbon nanotube array is used in a regime where it possesses properties of a uniaxial indefinite medium. We show that if the optical axis is tilted with respect to an interface, a plane incident wave propagates inside a finite-thickness slab of the carbon nanotube array with a very small wavelength and small material losses cause the total wave absorption. We demonstrate that perfect matching with free space can be achieved in an optically ultrathin layer without a magnetic response and when the reflected wave is absent. Nonsymmetry appearing as a difference between wave numbers of waves propagating upward and downward with respect to the interface under oblique incidence leads to the absence of a thickness resonance.