LEDs are bright, but they don't shine as bright as their potential. That's because when light emits from an LED, some of it gets reflected back inside.
To make LEDs brighter, researchers are taking a cue from the firefly. In fireflies, a chemical reaction makes the light, which then emits through the insect's exoskeleton, called the cuticle. Covering the cuticle are tiny scales that each have jagged edges. Each scale is about 10 micrometers long and makes a little slope that reaches 3 micrometers high. Computer simulations showed that the light at those edges was brighter.
A team of scientists from Belgium, France, and Canada, led by Annick Bay, decided to do something similar with LEDs. They put a layer of light-sensitive material on top of LEDs and then using a laser, created a sawtooth pattern, with each "peak" about 5 microns high. The structure minimized the reflection and boosted the LED's brightness by 55 percent.
The team isn't the first to look at fireflies. But previous efforts had focused on the tiniest structures of firefly skin, those at the nanometer scale, comparable to the wavelengths of light. This time, scientists went bigger: they looked at structures that were a thousand times larger.
The papers describing the work appear in the journal Optics Express.
Credit: Optics Express