Is Heat Necessary For Evaporation?

Everyone knows that when you heat water hard enough, it evaporates into vapour. But is heat the only stimulus that can trigger this process?

Researchers at MIT have recently found that, in the absence of heating, certain wavelengths of light itself can be used to cause the evaporation of water from materials known as hydrogels – porous, sponge-like substances capable of storing large volumes of liquid. Intriguingly, not only has light been shown to be more effective than heat at this task, but the rate of light-induced evaporation was observed to exceed the thermal limit; this is the highest theoretical amount of thermal evaporation possible from a given area, calculated using fundamental principles of physics.