Multi-Moiré imaging based on femtosecond laser-fabricated microlens arrays

Moiré fringe imaging plays a pivotal role in high-precision measurement, anti-counterfeiting, microstructural analysis, and optical metrology. However, conventional Moiré imaging devices are typically limited to generating a single image pattern. Here, we introduce a novel multi-Moiré imaging device capable of producing images with multiple distinct patterns and varying depths of field. We first elucidate the underlying mechanisms for magnification and axial image distance in Moiré imaging, based on the fundamental principles of the Moiré phenomenon generated by the superposition of microlens arrays (MLAs) and micro-pattern arrays. MLAs with good surface morphology were then fabricated using femtosecond laser-assisted wet etching. Leveraging these imaging principles, multi-pattern and multi-depth-of-field Moiré imaging devices were successfully produced. Finally, imaging characterization of the fabricated devices confirmed their exceptional performance, demonstrating promising potential for future applications in precision measurement, anti-counterfeiting, and observation.