Long wavelength infrared metalens fabricated by photolithography

Metasurfaces in the long wave infrared（LWIR）spectrum hold great potential for applications in thermal imaging，atmospheric remote sensing，and target identification，among others. In this study，we designed and experimentally demonstrated a 4 mm size，all-silicon metasurface metalens with large depth of focus operational across a broadband range from 9 μm to 11. 5 μm. The experimental results confirm effective focusing and imaging capabilities of the metalens in LWIR region，thus paving the way for practical LWIR applications of metalens technology.