Professor Namkyoo Park, develops a design method that can control the phase and amplitude of light (Digital Times, 2018.05.10)

2018-05-14l Hit 31

SNU College of Engineering (Dean Kookheon Char) announced on the 10th that the research team of Electrical and Computer Engineering Professor Namkyu Park developed an optical materials design method for the independent tailoring of the amplitude and phase information of light.
To manipulate light(wave) into intended form, it is necessary to design a suitable material(medium) such as lenses or magnifying glasses to control the direction and amplitude.
However, when light goes through a medium, the amplitude and direction change. This leads to differing the phase and thus limiting the maximum information capacity.
Professor Nam Kyu Park’s team took the interpretation on quantum mechanics to view optics in a different way. In reference to the fact that the 1929 Nobel prize winner de Broglie and theoretical physicist Bohm had tried to solve a similar problem in quantum mechanics in the form of ‘de-Broglie-Bohm Theory’, the team derived a new optical equation that can independently control the phase information and amplitude of light waves.
The first author of this paper Doctor Sunkyu Yu explained, “We first decomposed the optical material characteristics into two part: the phase(classical-like) counterpart and the energy(quantum-like) counterpart. Then the manipulation could be done separately, and the full-wave could be constructed by summing the two parts. As a result, we figured out that it was possible to control the phase distribution while setting a constant amplitude for the wave, or leaving the phase as constant and clustering or diminishing the light.”

Bohmian Photonics method that separates the optical medium that corresponds to the classical and quantum area for independent control / Photo courtesy of SNU

As explained before, the team proposed a scheme that can selectively control either the phase information or the light amplitude during a light-matter interaction. This research is practical in the sense that it made it possible to design the material structure inversely by deliberately setting the phase and amplitude beforehand. Also, it can be directly applied to the metamaterial design, which needs the zero refraction property.
Professor Namkyu Park said, “We proposed an innovative solution in an engineering problem using quantum mechanics interpretation from physics for optical research. This research can also be applied to designing resonators that can even convey phase information of incident rays, terahertz wave generation research for medical applications by rectification with phase control, and also other types of waves such as acoustic and matter wave.
The research was published in the renowned journal ‘Physical Review Letters’ which was posted online on May 10th. It was supported by the Ministry of Science and ICT’s Global Frontier Program for Extreme Wave Control and the Korean Research Fellowship Program, and the Ministry of Education’s Presidential Basic Science Fellowship Program.

ritten by Kyungjin Lee, Editor of Department of Electrical and Computer Engineering,