[POSTECH research team led by Professor Junsuk Rho demonstrates spin hall effect on arbitrarily polarized and unpolarized light.]

A POSTECH research team led by Professor Junsuk Rho and Ph.D. candidate Minkyung Kim of departments of mechanical engineering and chemical engineering has verified the optical spin-hole effect for the first time in randomly polarized or unpolarized incidence. This study was selected as the front cover paper of July issue of Laser and Photonics Reviews, an international journal on optics.

The spin hall effect of light (SHEL) refers to a transverse and spin-dependent shift of light to the plane of incidence when it is reflected or refracted at an optical interface. Most previous research has been limited to horizontally or vertically polarized incidence since SHEL depends on incident polarization.

The research team has proved analytically and numerically that the SHEL is independent of the incident polarization at the optical interface that satisfies a specific reflection condition, and that the SHEL occurs even under random and unpolarized light as in the case of horizontally or vertically polarized incidence. Since SHEL divides light into circularly polarized components, it can be used as optical device such as in optical switches and optical sensors. This study is significant in that it can extend the field of the SHEL – which was only studied in linearly polarized incidence – to include various polarized or unpolarized systems.

“We have demonstrated that the SHEL is independent of the incident polarization when a specific reflection condition is satisfied at the optical interface,” explained Professor Junsuk Rho. “This has broadened the applicability of the SHEL in next-generation optical systems.”

This research was conducted with the support from the Mid-career Researcher Program, Global Frontier Program, and Regional Leading Research Center (RLRC) Program of the National Research Foundation funded by the Ministry of Science and ICT of Korea.