Diffraction-limited broadband optical meta-power-limiter

In recent years, the need for a high-power laser has been of great interest for different applications, including direct-laser processing, light detection, medicine, and lighting. However, high-power lasers with high intensities give rise to fundamental problems for optical detectors and imaging systems with low threshold damage, which still need reliable solutions. Here we report and numerically demonstrate a hybrid system that synergistically combines a broadband OPL with a transmittance difference between on-state (70°C) and off-state (25°C) about 62.5%, and a diffraction-limited broadband metalens from 1534 to 1664 nm. Such a metalens power limiter could be used in any system requiring an intermediate focal plane in the optical path to the detector from damage by exposure to high-intensity lasers.