Joint Research Outcome Released by Prof. Choi Won-sik and Park Gyu-hwan's Team (Physics Department)
Paper Published in Nature Photonics July Issue

An innovative method of delivering light energy deep into the skin has been developed by a research team in Korea, possibly allowing a dramatic increase in the effectiveness of light-based disease treatment.

Prof. Choi Won-sik's team of the Physics Department (Kim Moon-seok (Ph.D.), Choi Young-woon (Ph.D.), Yoon Chang-hyung (Ph. D. student)) worked with Prof. Park Gyu-hwan's team (Ph.D. Choi Won-jun) at the same school and with Prof. Kim Jae-soon from the Physics Department of Myongji University to publish a joint paper in the July issue of Nature Photonics, the world's best optical science and photonics journal.

(*Title: Maximal Energy Transport through Disordered Media with the Implementation of Transmission Eigenchannels)

This research project was jointly supported by the Ministry of Education, Science and Technology and the National Research Foundation of Korea.

A disordered medium such as the skin tends to reflect most light, allowing only a very small amount of light into the skin. Therefore, there has been a limitation to the amount of light energy delivered to the depth desired in light-based disease treatment. In this regard, the research team split the incident light and differently adjusted it in each section. The research team successfully carried out this type of light amplification experiment for the first time in the world.

The team previously developed a new imaging method enabling viewing of an object behind a complex medium such as opaque glass (Physical Review Letters, 107 023902 (2011)). This technology allows an object (above figure on the left) underneath opaque glass to be clearly visible.(▲ Figure above: KU's Logo, Tiger)

The research this time took the imaging method a step further: Similar to the resonator modes in linear optical cavities, specific modes called eigenchannels exist in a disordered medium and have extraordinarily high transmission. The team used the eigenchannels to maximize light transmission.

In this way, four times more energy (below right figure) was transmitted than in a typical method. (below left figure).

Prof. Choi said, "This research is meaningful in that the long-debated existence of specific resonator modes were proven for the first time in the world, and it was by a team only composed of Korean researchers." He added, "This research is expected to contribute to the development of phototherapy."

▲ From left, Choi Won-sik (Prof.), Choi Won-jun, Kim Moon-seok, Yoon Chang-hyung, Park Gyu-hwan (Prof.)

★ Nature Photonics Journal
: Nature's sister journal specializing in optics and photonics. Its impact factor is 29.278 as of 2011, the highest in the optics and photonics area (SJR standard).