Thermal effects on metalenses

Metalenses, which are crucial for advancing miniaturization and enhancing performance in optical devices, have attracted considerable attention recently. However, the impact of temperature variations on metalenses (thermal effects) remains under-explored. In this study, we developed a theoretical framework to analyze these thermal effects using a linear thermal expansion model. To validate our framework, we performed finite element method simulations. In conventional lenses, thermal effects are considerably influenced by changes in refractive indices and/or surface curvatures. In contrast, our findings indicate that, for metalenses, thermal effects are mainly driven by the expansion of the substrate, with changes in index or deformation of the meta-atom being negligible. We believe that these insights will help guide the development of athermal hybrid lens systems, enabling robust performance across diverse temperature environments by effectively combining metalenses and conventional lenses.