To record over an existing recording, the amorphous spots are reheated by the recording laser to a temperature that allows them to recrystallise.

ECONOMIST: Digital video discs

In their latest experiment, Dr Sullivan and his colleagues painted the blades of a rotor with both temperature-and pressure-sensing paints, shone laser light on to them, and mapped out the temperatures and pressures as the blades whirred around as fast as 14, 000 rotations per minute.

ECONOMIST: Pressure paints

The polymers return to a pre-defined shape when heated to a certain temperature, and, when damage is detected, an infrared laser sends light through the network to the damaged area, triggers the shape-memory, and commands the area to repair the crack or tear -- regaining up to 96 percent of its original strength.

ENGADGET: Shape-memory polymer knows when it's hurt, fixes itself

Moreover, such a laser can be fine-tuned over a smaller range of wavelengths simply by varying its temperature.

ECONOMIST: Lasers