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POSTECH develops foundational next-generation light-source technology: Professor O'Dae Kwon's EE team creates an energy-saving blue photonic quantum ring laser that avoids eye fatigue, accelerating blue-laser commercialization for lighting, mobile phones and next-generation displays.
A Korean team has developed a next-generation laser light source that could replace LEDs, which have attracted attention for high power efficiency. Professor O'Dae Kwon (61) and doctoral student Young-Chun Kim (27) developed the first blue, soft three-dimensional vertical-cavity photonic quantum ring (PQR) laser, outperforming conventional LEDs.
The technology is expected to address major LED limitations. Whereas LEDs struggle to exceed megahertz response speeds, lasers reach hundreds of megahertz to gigahertz, allowing high-frequency modulation for lighting, phones and next-generation displays.
Gallium-nitride PQR lasers smaller than a few micrometers are integrated in a honeycomb arrangement. Unlike ordinary lasers, they do not cause dazzling, shimmering speckle and thus avoid eye fatigue. An optical-wave ordering effect enables operation at microampere to nanoampere currents, lowering consumption, while wavelengths remain stable above 150°C.
Using three-dimensional “whispering cave” resonance instead of conventional two-dimensional “whispering gallery” resonance reduces sensitivity to material reflectivity, a major obstacle in laser applications. Existing LED wafers can therefore be used instead of dedicated laser wafers, improving commercialization prospects.
The team explained that unlike LEDs, which require surface modification or etching to improve light extraction, the lasers use regular device processing without extra surface processes. This should avoid surface-induced problems, improve reliability and reduce production costs.
While Japan holds most foundational LED patents, the Korean team holds PQR laser-source patents in Korea, the United States and Japan, making this a distinctive foundational technology. Kwon plans to present these results and the world's lowest-current megapixel laser chip in an invited talk at SPIE Photonics West 2008 in San Jose, California, on the 22nd.
Dr. Jong-Hyup Baek's team at the Korea Photonics Technology Institute participated. Support came from the Ministry of Science and Technology/Korea Science and Engineering Foundation National Research Laboratory program, the Ministry of Education and Human Resources Development BK21 program, the nanotechnology integration center, Samsung Electronics and LG Innotek.