Nanoimprinting of pressure-intolerant tilted nanostructures assisted by an electric field for high performance optical coupler.

Tilted nanostructures, with their unique light-modulating capabilities, find broad applications in optical fields such as optical couplers, and escalating performance demands of devices impose formidable challenges regarding structural fidelity and fabrication cost-effectiveness, owing to their inherent pressure-intolerant properties. Here, a novel electric-field-assisted nanoimprinting technique is proposed. The electric-induced "interface-tension-driven" active resist filling of template microcavities is fundamentally different from the traditional nanoimprinting technique. This paradigm shift enables simultaneous mitigation of structural deformation induced by pressure and preclusion of residual layers, thereby resolving the intrinsic conflict between low-stress deformation control in tilted nanostructures and high-pressure residual layer elimination. Furthermore, a demolding path optimization strategy is proposed to effectively minimize stress-induced damage to tilted nanostructures during the demolding process. Based on the optimized filling and demolding processes, the developed nanoimprinting prototype enables real-time process parameter adjustment according to target geometries, resulting in high-fidelity, residual-layer-free fabrication of various tilted nanostructures. The integration of custom-fabricated tilted nanostructures into augmented reality (AR) systems results in remarkable performance enhancement, highlighting the substantial application potential of this technique in high-performance optical couplers and advanced nanomanufacturing.