Optical metasurfaces: new generation building blocks for multi-functional optics

Optical metasurfaces (OMs) have emerged as promising candidates to solve the bottleneck of bulky optical elements. OMs offer a fundamentally new method of light manipulation based on scattering from resonant nanostructures rather than conventional refraction and propagation, thus offering efficient phase, polarization, and emission control. This perspective highlights state of the art OMs and provides a roadmap for future applications, including active generation, manipulation and detection of light for quantum technologies, holography and sensing. Materials with ‘optical metasurfaces’ (OMs) have surface layers patterned at scales smaller than the wavelength of light, offering fundamentally new ways to manipulate light for many possible applications. Conventional optics generally relies on light being refracted as it passes through materials, or simply reflected from surfaces. Igor Aharonovich at the University of Technology Sydney, and Dragomir Neshev at the Australian National University, Canberra, review the current capabilities and likely future applications of OMs. The authors themselves investigate light capture, scattering and re-emission by OMs to control aspects of light including its phase, polarization and emission characteristics. They foresee new ways to control the properties of light serving to advance technologies including those that exploit the subtle quantum mechanical properties of light. Innovative optical sensors and holography systems are among the many potential uses of OMs.