Phys.org October 16, 2024
Nonlinear metasurfaces are used for infrared imaging and spectroscopy. However, due to their low conversion efficiencies several strategies have been adopted to enhance their performances. Using resonances at signal or nonlinear emission wavelengths results in a narrow operational band of the nonlinear metasurfaces, which has bottlenecked many applications, including nonlinear holography, image encoding, and nonlinear metalenses. An international team of researchers (UK, Australia) introduced a new nonlinear imaging platform to overcome this issue. They demonstrated broadband nonlinear imaging for arbitrary objects using metasurfaces. A silicon disk-on-slab metasurface was introduced with an excitable guided-mode resonance at the pump wavelength. This enabled direct conversion of a broad IR image ranging into visible. Adopting four-wave mixing (FWM) substantially reduced the dependence on high-power signal inputs or resonant features at the signal beam of nonlinear imaging. According to the researchers their results unlocked the potential for broadband infrared imaging capabilities with metasurfaces, a promising advancement for next-generation all-optical infrared imaging techniques with chip-scale… read more. Open Access TECHNICAL ARTICLE
The fabricated Si metasurface and its band structure. Credit: Light: Science & Applications volume 13, Article number: 249, 10 September 2024Â