Electrochemically-Controlled Metasurfaces for High-Contrast, Fast-Switching Optical Applications

Traditional optical systems rely on static elements, such as lenses and prisms, which are limited in adaptability and miniaturization. With increasing demands for dynamic, lightweight, and energy-efficient solutions, metasurfaces have emerged as a transformative technology. Despite their promise, most active metasurfaces exhibit limited performance at visible frequencies. By introducing electrochemically-controlled designs, this invention overcomes challenges in switching speed, optical contrast, optical reconfigurability and operational efficiency. The integration of dynamic materials like PANI enhances the responsiveness and scalability of these optical elements, paving the way for real-world photonic applications.

The technology features an advanced metasurfaces composed of goldnanorods precisely arranged on an ITO-coated quarts substrate. These nanorods are organized in altering rows, with one set statically coated in a dielectric polymer such as polymethyl methacrylate (PMMA) and the other dynamically tunable through a coating of a second substance such as PANI (Fig. 1). PANI's refractive index can be electrochemically adjusted, enabling active control of light transmission, reflection, and phase shifting. This design facilitates high-intensity contrast ratios (up to 860:1) and fast switching speeds (approx. 35 – 48 milliseconds) (Fig. 2B). Additionally, the metasurfaces demonstrate exceptional reversibility over multiple switching cycles, making them highly durable and efficient for optical modulation tasks (Fig. 2C).

• High-contrast light modulation: PMMA/ PANI system achieves intensity contrast ratios exceeding 860:1 (Fig. 2A).
• Fast switching: Speeds of approx. 40 milliseconds were shown exemplary (Fig. 2B).
• Compact and lightweight: Ultrathin metasurface design suitable for space-constrained applications.
• Reversible and durable: Maintains performance over extensive switching cycles (Fig. 2C).
• Cost-effective and scalable: Utilizes affordable, easily synthesized materials like PANI.

• Dynamic lenses and zoom optics: Enabling electrically controlled adjustments of focal length and focus.
• Extended Frequency Ranges: Adaption of metasurface technology for various spectral regions, from visible to infrared light.
• Dynamic holography for imaging and communication systems.
• High-speed optical sensors for medical and industrial use.
• Photonic displays with tunable resolution and brightness.
• Light-based data communication networks.

PCT application (WO2022128410A1; 26.11.2021)

Li et al., „Electrically-controlled dynamic optical component comprising a metasurface,” US Patent 20240053510, 26. November 2021.
Kaissner, Robin, et al. "Electrochemically controlled metasurfaces with high-contrast switching at visible frequencies." Science Advances 7.19 (2021): eabd9450.