UNIST Develops World's First Electrically Controlled Metasurface Technology... Creating Ultra-Thin Quantum Light Sources

World's First Development of Third Harmonic Control Technology for Light Brightness and State

Light Frequency Freely Adjustable... Realizing Quantum Light Sources and Hologram Technology

The UNIST research team has succeeded in developing an active-tunable nonlinear optical metasurface technology composed of structures smaller than the wavelength of light.

This breakthrough is expected to bring significant advancements to future communication technologies, including quantum light sources and medical diagnostic devices.

The team led by Professor Lee Jongwon from the Department of Electrical and Electronic Engineering at UNIST (President Park Jongrae) has developed a 'nonlinear optical metasurface' capable of electrically controlling third harmonic generation. This technology enables the manipulation of complex optical signals by altering the properties of light in response to external signals or stimuli.

Professor Jongwon Lee, Department of Electrical and Electronic Engineering, UNIST.

Nonlinear optics refers to the interaction between light and matter that changes the frequency of light. By generating various wavelengths, it can transmit more information than single-wavelength lasers. A green laser pointer is a representative application that utilizes nonlinear optical technology.

A metasurface consists of a metal structure combined on a thin semiconductor layer, with dimensions smaller than the wavelength of light. Arranged in multiple units on a substrate, metasurfaces can manipulate light effectively.

Nonlinear optical metasurfaces enable optical devices to be made smaller and lighter. Laser devices can be fabricated as thin as paper using artificial materials thinner than a human hair. While traditional passive methods made electrical control difficult, the nonlinear optical metasurface developed by the research team can be controlled electrically.

The team is the first in the world to introduce technology that can control the second harmonic using voltage, and now they have also implemented technology to independently control the intensity and phase of the third harmonic for the first time. This means that metasurfaces can now control not only the wavelength but also the intensity and phase of light.

Schematic diagram of a third harmonic generation nonlinear optical metasurface with electrical tunability.

Researcher Park Sungjin explained, "The characteristics of optical metasurfaces are determined by the semiconductor layer and metal structure," adding, "Metasurfaces have surpassed the limitations of conventional optical devices by controlling not only the frequency of light but also its phase and amplitude."

Professor Lee Jongwon said, "This is the first time the intensity and phase of nonlinear third harmonics have been electrically controlled," and added, "It can also be applied to optical modulation encryption technology, moving holograms, next-generation quantum sensors, and quantum communication light sources."

The research results were published as a paper on July 17 in 'Light: Science and Applications,' the most prestigious journal in the field of optics. The research was supported by the National Research Foundation of Korea's Mid-Career Researcher Support Program and other initiatives.

This content was produced with the assistance of AI translation services.