Lessons from nature: biomimetic subwavelength structures for high‐performance optics

TLDR

Natural subwavelength optical structures, such as moth‑eye patterns, have evolved to provide strong anti‑reflective protection for insects and recent advances in top‑down and bottom‑up fabrication techniques have enabled optimal profile designs. This work examines the advantages and challenges of translating these natural subwavelength concepts into high‑end optical systems. The authors combine theoretical optimization of subwavelength profiles with the development of top‑down and bottom‑up fabrication methods, enabling anti‑reflective structures to be applied to a wide range of optical elements from micro‑components to aspheres in imaging and illumination systems. Compared to conventional multilayer coatings, the bioinspired anti‑reflective structures provide a broader wavelength range, wider angular tolerance, and dramatically reduced adhesion issues.

Abstract

Abstract In nature, optical structures in the subwavelength range have been evolved over millions of years. For example, in the form of ‘moth‐eye’ structures they show a strong anti‐reflective effect on the compound eyes of night‐active insects and therefore offer a successful protection over predators. In this contribution the advantages and challenges to transfer this natural concept of subwavelength structured optical interfaces to high‐end optical systems are discussed. Here, in comparison to alternative conventional multilayer systems, the bioinspired anti‐reflective structures offer a wide wavelength range and a broad angle dependency. Additionally, adhesion problems are reduced drastically. Simultaneously to the theoretical consideration of the best profile form of the subwavelength structures, appropriate realization technologies have been developed in recent years, where both top‐down and bottom‐up approaches have been investigated. Depending on the choice of the structuring technique, anti‐reflective subwavelength structures are applicable to a wide spectrum of optical elements ranging from micro‐optical components to aspheres for applications in imaging and also illumination setups of high‐end optical instruments.