What a bright idea

SCI Chemistry & Industry features "What a bright idea"

"Thomas Alva Edison’s incandescent light bulb, patented in 1879, has served us well for more than a century. But, in the modern eco-conscious environment, it is fantastically wasteful – turning 98% of the electricity into heat rather than light."

"One promising alternative approach is the superluminescent light-emitting diode (SLED), which avoids the efficiency droop as well as other technical problems of the LED. This device is built like a laser diode – as in CD and DVD players – and uses some amplification by stimulated emission, but it deliberately lets light leak out of the chamber before lasing sets in. Invented in the 1980s, SLEDs are already used in highly specialised applications such as optical gyroscopes. They may also have a future for mass-market applications, as they appear to combine the energy-efficient and user-friendly properties of LEDs with the droop-resistance of laser diodes."

"The group of Boon Ooi at the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, in collaboration with researchers at the University of California at Santa Barbara, US, including blue-LED inventor Shuji Nakamura, has recently demonstrated the fabrication of such a high-performance diode with InGaN/GaN quantum wells using metal-organic chemical vapour deposition."

"The resulting high-powered blue light can be converted to white light with conventional phosphors such as YAG, just like in a blue LED. The resulting white light is unaffected by the drooping problem found in LEDs as well as the spatial unevenness or ‘speckle’ of laser diode based lights. Therefore, the authors conclude that this novel device will be suitable both for optical communications and for general lighting purposes."

High-brightness semipolar (2021) blue InGaN/GaN superluminescent diodes for droop-free solid-state lighting and visible-light communications
Chao Shen, Tien Khee Ng, John T. Leonard, Arash Pourhashemi, Shuji Nakamura, Steven P. DenBaars, James S. Speck, Ahmed Y. Alyamani, Munir M. El-desouki, and Boon S. Ooi
Optics Letters, 41(11), 2608-2611 (2016)

DOI: 10.1364/OL.41.002608