Recent advancements in nonlinear optical metasurfaces have been groundbreaking, offering a glimpse into the future of communication technologies and medical diagnostics. With features smaller than the wavelength of light, these innovative structures facilitate the generation of multiple wavelengths from a single source, significantly augmenting information transmission capabilities compared to traditional laser systems.
A pivotal study led by Professor Jongwon Lee from UNIST has made significant strides by producing electrically tunable third-harmonic generation (THG) using a unique intersubband polaritonic metasurface integrated with multiple quantum wells (MQWs). Published in *Light: Science & Applications*, the research highlights a modulation depth of 450% in the THG signal—a remarkable feat. Furthermore, the researchers achieved an impressive 86% suppression of zero-order THG diffraction while demonstrating local phase tuning exceeding 180 degrees. This capability not only enhances the flexibility of optical devices but also introduces a novel method for steering THG beams by utilizing phase gradients.
The significance of nonlinear optics cannot be understated; it facilitates the generation of multiple wavelengths, paving the way for innovations in various fields including quantum sensor technologies and cryptography. The new metasurface technology is a distinct departure from previous techniques that faced challenges with electrical modulation, marking a crucial step towards the ultimate integration of photonics and electronics.
The lightweight and compact design of optical instruments enabled by this technology allows for devices that could rival the thickness of a sheet of paper, employing materials thinner than human hair. This unprecedented control over the properties of light could see applications in diverse areas, from dynamic holography to advanced quantum communication light sources.
Professor Lee has heralded this development as a breakthrough, stating, “This advancement allows for unprecedented control of light.” The introduction of the world’s first voltage-controlled second-harmonic generation (SHG) with independent modulation over both intensity and phase marks a significant leap in nonlinear optical elements. The ability to manage not only the wavelength but also the intensity and phase of light represents a quantum leap in technological capabilities.
Co-researcher Seongjin Park reiterated the importance of the interplay between semiconductor layers and metal structures, underscoring that the properties of these optical metasurfaces stem from their intricate design. This level of customization not only enhances the performance but also allows tailoring for specific applications.
The advancements in nonlinear optical metasurfaces herald a new era in optical technology. By offering enhanced control and modulation capabilities, this innovation stands to influence a wide range of industries, from telecommunications to healthcare. As researchers continue to explore the potentials of these advanced materials, the promise of groundbreaking applications looms on the horizon, reshaping our understanding of light manipulation and its practical uses in modern science and technology.