Temperature-responded tunable metalenses based on phase transition materials

Abstract

Once the metalenses are fabricated, the functions of most metalenses are invariable. The tunability and reconfigurability are useful and cost-saving for metalenses in realistic applications. We demonstrate this tunability here via a novel hybrid metalens with the strategic placement of an ultra-thin VO2 layer. The hybrid metalens is capable of dynamically modulating the focusing intensity of transmitted light at a wavelength of 1550 nm, and demonstrate a 42.28% focusing efficiency of the incident light and 70.01% modulation efficiency. The hybrid metalens’ optothermal simulations show an optothermal conversion process of dynamic focusing, and a maximum laser density of 1.76×103 W/cm2 can be handled at an ambient temperature lower than 330 K. The hybrid metalens proposed in this work, a light-dose sensitive tunable smart metalens that can protect other instruments/systems or materials from being damaged, has its specific applications such as in anti-satellite blinding, bio-imaging, etc.