Advances in Femtosecond Laser Micro-Nano Machining for Optical Microstructure Fabrication

Abstract

Ultrafast femtosecond lasers feature ultrashort pulses, ultrahigh peak power and cold ablation, and have evolving into a vital precision machining tool in optoelectronic engineering. This paper reviews femtosecond laser fabrication of optical microstructures including microlens arrays, photonic crystals and microgratings. It elaborates the cold processing mechanism of femtosecond lasers and analyzes how laser energy, scanning speed and repetition rate modulate microstructure morphology. Domestic and international mainstream process optimization strategies are compared, and existing bottlenecks such as low machining efficiency and surface microdefects are summarized. The research verifies that proper matching of laser parameters with an assistive gas atmosphere remarkably reduces microstructural defects and improves optical transmittance. Finally, this work sorts out current research trends and proposes feasible paths to balance processing quality and efficiency, offering references for high-precision manufacturing of functional optical microdevices.