Using patterned carbon nanotube films with optical anisotropy to tune the diffracted color from flexible substrates

We combine transverse electric (TE) and transverse magnetic (TM) polarized light of various incident angles with optical thin film theory to investigate the optical anisotropy of carbon nanotube (CNT) films. We also determined the relationship between the optical anisotropy and diffraction phenomena in grating-patterned CNT films. For TE polarized light, the diffraction intensity remains almost unchanged upon varying the incident angle. For TM-polarized light, however, the diffraction intensity decreases upon increasing the angle of incidence. We deform and bend flexible substrates to induce dynamic modulation of the diffraction colors from the CNT gratings. Convex bending of the surface increases the period of the CNT gratings, thereby causing more penetration of diffracted light; concave bending decreases the period of the CNT gratings, causing the diffracted light to weaken in intensity in the CNT forest.