Miniaturized spectroscopy systems that can detect trace concentrations at the parts-per-billion (ppb) level are of utmost importance in applications ranging from environmental monitoring and industrial process control to biomedical diagnostics. However, the existing bench-top spectroscopy systems are too large, complex, and impractical for narrow-space use. Furthermore, the traditional laser spectroscopy techniques use bulky components like light sources, mirrors, detectors, and gas cells to detect light absorbed or scattered by a sample, which makes them unsuitable for scenarios calling for minimal invasiveness such as intravascular diagnosis.

Plasmons are collective oscillations of electrons in a solid and are important for a wide range of applications, such as sensing, catalysis, and light harvesting. Plasmonic waves that travel along the surface of a metal, called surface plasmon polaritons, have been studied for their ability to enhance electromagnetic fields. One of the most powerful tools for studying these waves is time-resolved electron microscopy, which uses ultrashort laser pulses to observe how these plasmonic waves behave. An international research team recently pushed the boundaries of this technique.

Modern imaging systems, such as those used in smartphones, virtual reality (VR), and augmented reality (AR) devices, are constantly evolving to become more compact, efficient, and high-performing. Traditional optical systems rely on bulky glass lenses, which have limitations like chromatic aberrations, low efficiency at multiple wavelengths, and large physical sizes. These drawbacks present challenges when designing smaller, lighter systems that still produce high-quality images. To overcome these issues, researchers have developed metalenses—ultra-thin lenses composed of tiny nanostructures that can manipulate light at the nanoscale. Metalenses offer tremendous potential for miniaturizing optical systems, but they are not without their own challenges, particularly when it comes to capturing full-color images without distortions.

Researchers have long sought to harness the power of light for computing, aiming to achieve higher speeds and lower energy consumption compared to traditional electronic systems. Optical computing, which uses light instead of electricity to perform calculations, promises significant advantages, including high parallelism and efficiency. However, implementing complex logic operations optically has been a challenge, limiting the practical applications of optical computing.