Optical transmission and selective reflection data are reported for dispersions of single-walled carbon nanotubes (SWCNT) in cholesteric liquid crystals comprising a mixture of cholesterol esters and azoxy nematic ZhK-440. The optical density was shown to be essentially non-linear with SWCNT concentration, with a minimum ascribed to formation of "stacked" aggregates of nanotubes. The location of this minimum, as well as the selective reflection maximum (helical pitch), are sensitive to partially reversible UV-induced trans-cis-trans isomerisation effects. The UV-controlled helical pitch variation was shown to be only slightly affected by introduction of carbon nanotubes. Application prospects of such materials in optoelectronic devices are considered.
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