Traditional cell observation under a microscope requires the manual rotation of the equipment and the replacement of parts whenever the observation mode is switched. However, a lens has now emerged that allows the microscope’s observation method to be freely changed using only voltage. The research team led by Professor Junsuk RHO (ME, CE, EE, CiTE) has successfully developed switchable metalens that can toggle between different microscopy modes using only an external voltage.

The research team focused on ultra-thin metalens. Metalens are next-generation optical devices that control light using nanometer-level microstructures. However, they had a limitation in that their functionality became fixed once fabricated. To overcome this limitation, the research team introduced a conductive polymer into the interior, whose light absorption characteristics change depending on the voltage.

They designed the device to precisely control the amount of light passing through the center of the lens according to the voltage. In brightfield mode, the flat overall shape of the cell was emphasized, while in darkfield mode, the cell nucleus and internal structure were highlighted; in semi-darkfield mode, both types of information were captured simultaneously within a single image. The biggest advantage of this technology is that it requires less than 1V to operate.

This research is expected to be applied to bio-diagnostic devices that allow the observation of blood cells or bacteria at home without visiting a hospital, and sensors used in autonomous vehicles and drones. Prof. RHO stated, “This research is a significant achievement demonstrating that the multifunctionality of metalens imaging can be realized at low voltage; it will evolve into an ultra-compact optical platform applicable in real-world settings.” This research was published in ACS Nano.