SEM image of an aligned MWNT sheet that was drawn from an MWNT forest, photograph of the 2.5×5 cm² MWNT sheet between two copper electrodes, and blackbody emission of the resistively heated (_˜1650 K) sheet.

Photothermal deflection (PTD), otherwise known as the mirage effect, is a naturally occurring optical phenomenon caused by the refraction gradient created by a hot surface. The photograph shows an underwater mirage effect created by 5×12 cm² MWNT sheet heated with 6W of power. The non-wetted surface of carbon nanotubes allows fast thermal switching of the very thin surrounding water layer.