Transparent and Flexible Photon Sieve Made with Cellulose Nanofiber by Micro-Nano Structure Molding

Conventionally, the photon sieve (PS) was made of chrome-coated fused silica and quartz plates. However, fused silica and quartz plates have a size limitation due to their weight and fragility. A membrane PS is attractive since it is lightweight, large size, flexibility and deployable. This paper demonstrates the new concept of membrane PS based on cellulose nanofiber (CNF). The CNF-based PS (CNF-PS) is transparent, flexible, lightweight, and has high strength and toughness. This study highlights the PS fabrication on a CNF film using a micro-nano structure molding technique and its structural stability in an external environmental change. For the first time in literature, through a high vacuum (5 × 10–8 Torr) environment test, it was shown that CNF has emerged as a promising optical material. Furthermore, the prepared CNF-PS exhibited high beam quality. This study explained the complete research strategy from the isolation of cellulose nanofibers to its PS application. The new concept of CNF-PS will accelerate its broad application to thin and compact photonic devices.