posted on 2024-04-03, 13:33authored byJianchao Zhang, Qian Sun, Zhengyang Wang, Guangyong Zhang, Yikun Liu, Jin Liu, Emiliano R. Martins, Thomas F. Krauss, Haowen Liang, Juntao Li, Xue-Hua Wang
Metalenses are typically designed for a fixed focal length,
restricting
their functionality to static scenarios. Various methods have been
introduced to achieve the zoom function in metalenses. These methods,
however, have a very limited zoom range, or they require additional
lenses to achieve direct imaging. Here, we demonstrate a zoom metalens
based on axial movement that performs both the imaging and the zoom
function. The key innovation is the use of a polynomial phase profile
that mimics an aspheric lens, which allows an extended depth of focus,
enabling a large zoom range. Experimental results show that this focal
length variation, combined with the extended depth of focus, translates
into an impressive zoom range of 11.9× while maintaining good
imaging quality. We see applications for such a zoom metalens in surveillance
cameras of drones or microrobots to reduce their weight and volume,
thus enabling more flexible application scenarios.