U.S. Army researchers have developed micro materials that fold when hit with a low-intensity laser. The advance may eliminate the need for relatively bulky power systems—such as battery packs—on tiny robotic systems. It also could enable robotic microthrusters, unattended ground sensors, or even—theoretically—programmable, easily changeable camouflage patterns.
The microelectromechanical systems (MEMS) are shaped like stars with four, six or eight legs. The legs fold—like origami—when heated slightly with light from a low-level laser. That folding action is accomplished without the materials being tethered to batteries, wires or other any other power supply.
One of the most likely applications would be a new kind of switch that prevents electricity leakage when a device is turned off. “You could turn on a structure or turn off a structure from a distance by shining a light on it,” explains Chris Morris, an Army Research Laboratory (ARL) electronics engineer who leads the On-chip Energetics and MEMS team. “And when the structure is in an off state, it would be truly off, unlike a solid-state electrical switch where there’s always some leaking through even when it’s off.”
Microrobotic applications are more futuristic. “I could see this as potentially being a way to enable very, very small robotic-like platforms where you have little legs that would move in response to light—and potentially even different colors of light, so they could be directed to walk in one direction or another depending on what color of light you’re flashing at them,” Morris explains. “That’s one interesting aspect that circumvents the current power supply challenge with small-scale robotic systems for surveillance and reconnaissance. The power supplies are so bulky and heavy that in order to get something big enough to carry the power supply, you no longer have a small, cheap, disposable package. You have something the size of a kid’s remote-control car.”