Review of Surface Modification Technologies for Mid‐Infrared Antireflection Microstructures Fabrication

Mid-infrared materials antireflection is in high demand for high-powered or ultra-broadband coherent light sources, where conventional antireflection coatings cannot be reliably applied. This work provides a critical review of the recent advances in microstructure fabrication technology for mid-infrared antireflection applications. Several techniques are reviewed, including direct imprinting, wet and reactive ion etching using conventional photoresist masking, novel colloid crystal masks, and maskless etching, laser-induced periodic structure formation, and multiple laser ablation method modifications, including femtosecond laser direct writing, direct laser interference ablation, and single pulse ablation. The advantages and drawbacks of the different approaches are discussed in detail to highlight the most promising techniques for the fabrication of antireflection microstructures capable of achieving 99% transmittance in the 2–16 μm range.