Carbon Nanotubes
Certain species of carbon nanotubes also undergo photochemical reactions when exposed to intense pulsed light from a laser, arc lamp, or flashbulb. In the presence of air, Carbon Nanotubes will undergo combustion at high temperature (700-1500C). Under inert atmospheres, the nanotubes will break open and reorganize into larger "nanohorn" structures.
Read more about this topic: Photochemistry