Liquid crystal metasurfaces

Metasurfaces are engineered materials with unique physical properties not found in conventional materials. These characteristics transform the interaction between light and matter, allowing for the manipulation of electromagnetic waves in highly unpredictable ways. This capability has a significant impact on various fields, ranging from advanced diagnostics to automotive applications. Among metasurfaces, reconfigurable ones are especially noteworthy due to their reliability in real-world applications. Implementing these metasurfaces involves integrating stimulus-responsive materials, such as liquid crystals (LCs), which provide the necessary reconfigurability. However, developing more scalable and cost-effective fabrication methods for metasurfaces to be used practically is essential. This manuscript discusses state-of-the-art fabrication processes for metasurfaces, with a focus on bottom-up metasurfaces, which are challenging yet promising materials with significant technological relevance. Moreover, this work highlights several examples that combine LCs with bottom-up metasurfaces, resulting in active and tunable metadevices. This manuscript is a valuable resource for emerging design and fabrication strategies to develop next-generation reconfigurable metasurfaces for practical use.