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This year's Nobel Prize in Physics was awarded to scientists who invented the blue LED in the early 1990s, which promoted the development of a new generation of bright, energy-efficient white fluorescent lamps and color LED screens. However, the slow speed of this huge research result in switching has limited its use as a light source-based communication. In an LED, a blink of an eye is forced to emit about 10 million photons. Modern communication systems run nearly a thousand times faster than LEDs emit photons. In order to achieve LED-based optical communication, researchers must speed up photonic luminescent materials.
In the new study, engineers at the university accelerated their photon emissivity to unprecedented levels by adding fluorescent molecules between the metal nanocubes and the gold film. "The goal of this research is to use ultra-high-speed LEDs, although the future equipment may not use this precise method, but it is critical to basic physics," said McKenn Mickelson, assistant professor of electrical and computer engineering and physics at the university. important."
Mickelson is an expert in studying the interaction between electromagnetic fields and free electrons in metals. According to a report by the physicist organization network on October 13, in the experiment, his team made 75 silver nanocubes and trapped the light inside, greatly increasing the intensity of light. When fluorescent molecules are placed next to dense light, the velocity at which the molecules emit photons is enhanced by the "Purse effect". They found that by placing fluorescent molecules between the gap between the gold film and the nanometal, their speed can be significantly improved.
To achieve maximum effect, the researchers need to adjust the resonant frequency of the gap to match the colored light of the molecular response. With the help of the co-author of the paper, the professors of electrical and computer engineering at the university, David Smith, and Director James B, computer simulations were used to accurately determine the required gap size between the nanocube and the gold film: only 20 Atomic width. The researchers said: "We can choose a cube with the right size, so that the gap has nano-scale accuracy, thus a record increase in fluorescence speed of 1000 times."
Because the experiment used many randomly arranged molecules, the researchers believe that they can do better. They plan to place individual fluorescent molecules precisely in a single nanocube to achieve a higher rate of photons emitted by fluorescent molecules.
The researchers said: "If we can accurately set the molecule, it will not only be a fast LED, but also many applications. For example, to manufacture a fast single photon source for quantum cryptosystems, this technology will support secure communication and avoid hacking. ." 
Researchers at Duke University in the United States have recently developed ultra-fast light-emitting diodes (LEDs) that break the speed record of photons emitted by fluorescent molecules, which is 1000 times that of ordinary grades, and is an important step toward achieving ultra-fast LED and quantum cryptography. The results of the study were published online October 12 in Nature Photonics.