Quasi Crystalline Diffraction from Nanotube Arrays

6 Quasi Crystalline Diffraction from Nanotube Arrays 

A very effective demonstration of enhanced plasmonic effects from laterally illuminated MWCNTs has been demonstrated by the diffraction patterns observed from a 2D Penrose tiled quasicrystal structure [29]. This stmcture has been seen 

The calculation of the diffraction pattern for a periodic system revolves around the construction of the reciprocal lattice and subsequent placement of the first Brillouin zone however, in this case the aperiodicity of the pentagonal array requires a different approach due to the lack of translational symmetry. The reciprocal lattice of such an array is densely filled with reciprocal lattice vectors, with the consequence that the wave vector of a transmitted/reflected light beam encounters many diffraction paths. The resultant replay fields can be accurately calculated by taking the FT of the holograms. To perform the 2D fast Fourier transform (FFT) of the quasi-crystalline nanotube array, a normal scanning electron micrograph was taken, as shown in Fig. 1.13. 

The remarkable richness and intricacy of the optical replay field emanating from the quasi-crystalline MWCNT array is best seen in the spherical diffraction pattern shown in Fig. 1.15. The results clearly show that the quasiperiodic array of nanotube antennas act as holograms (apertures) for the reflected light, producing remarkable and striking diffraction patterns (replay fields). 

This makes both the electric and magnetic field components nonnal to the MWCNT axis. 

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