The United States uses metamaterial design to make LED light like a laser to achieve more efficient steam

According to foreign media reports, researchers at the University of California, Santa Barbara (UCSB) will use a new method to break through the boundaries of LED design, which may lead to more efficient and functional LED displays and more Lighting technology paves the way.

(Source: University of California, Santa Barbara)

UCSB Professor of Electronic and Computer Engineering Jonathan Schuller and his collaborators described the new method, which can make virtual reality (VR) headsets, automotive lighting and other LED devices more sophisticated and fashionable.

Schuller said: "We are showing a new type of photon structure, which not only can extract more photons, but also can lead the photons to the ideal place." He also explained that the external light that is usually used to control the light emitted by the LED is not used Encapsulated components improve this performance.

The light in the LED is generated when the semiconductor material is excited. When the negatively charged electrons moving along the semiconductor lattice encounter positively charged holes (no electrons) and change to a lower energy state, here A photon is released during the process. When measuring the process, the researchers found that a considerable number of photons were being produced, but not from the LED.

Schuller said: "We realized that if we look at the angular distribution of the emitted photons before forming the pattern, we often find that the photons peak in a specific direction, which is usually trapped in the LED structure. Therefore, we realized Traditional supersurface concepts can be used to design light that would normally be trapped."

The design identified by the researchers included a set of 1.45 micron GaN nanorods on a sapphire substrate. A quantum well made of indium gallium nitride (InGaN) is embedded in the nanorod to confine electrons and holes and emit light. In addition to allowing more light to leave the semiconductor structure, the design can also achieve polarized light, which is critical for many applications.

Iyer came up with the idea for the project when he completed his doctorate in the Schuller laboratory a few years ago. The research focus of this laboratory is on photonics technology and photon phenomena in the sub-wavelength range. The metasurface is an engineering surface with nanoscale features and capable of interacting with light, which is also the focus of Iyer's research.

Iyer has been studying how to use a super surface to guide the laser beam. He said: "In essence, the super surface is a subwavelength antenna array." He also learned that typical super surfaces rely on the highly directional characteristics of the incident laser beam. To produce a highly directional output beam.

On the other hand, the LED will emit self-luminescence, which is different from the stimulated coherent light of the laser.

Schuller explained: "Spontaneous emission samples all possible movements of photons, so light looks like a beam of photons that can move in all possible directions. The question is whether careful nanoscale design and semiconductor surfaces Manufacturing, directing the generated photons to the desired direction?"

Iyer said: "Someone has designed LEDs before, but they always divide the LED light into multiple directions, which is very inefficient. No method has been designed to control the LED light to be emitted in one direction." (Yu Qiuyun)