Thermally Reconfigurable Hologram Fabricated by Spatially Modulated Femtosecond Pulses on a Heat-Shrinkable Shape Memory Polymer for Holographic Multiplexing

Abstract

Optical security involving the use of light to achieve distinctive vision effects has become a widely used approach for anticounterfeiting. Holographic multiplexing has attracted considerable interest in multiplexing security due to its high degree of freedom for manipulating the optical parameters of incident laser beams. However, the complex and time-consuming fabrication process of metasurface-based holograms and the sophisticated nature of holographic imaging systems have hindered the practical application of holographic multiplexing in anticounterfeiting. Combining holography with shape memory polymers to construct reconfigurable holograms provides a simple and efficient way for holographic multiplexing. This paper proposes a reconfigurable fourlevel amplitude hologram fabricated on a heat-shrinkable shape memory polymer using spatially modulated femtosecond laser pulses. Simply by triggering the shape recovery of the polymer through heating, the amplitude modulation of light by the hologram is reconfigured through the shrinking of processed microcrater pixels with three diameters, which enables variation to be achieved in reconstructed holographic images. Examples of holographic multiplexing and data encryption are used to validate the proposed method. The proposed economic and simple approach for holographic multiplexing provides an integrated and single-material solution to packaging and optical security, which has extensive potential in anticounterfeiting and optical encryption.

Smart Fibers and Textiles for Personal Thermal Management in Emerging Wearable Applications

“…In nature, butterflies can change the opening and closing state of the scales on their wings according to changes in the environment to control their body temperature. [ 53–55 ] Inspired by this smart behavior, Song et al. gave shape memory function to a certain material, exhibiting excellent response to the stimulus, and can change its shape under external stimulus.…”

Current and Future Trends for Polymer Micro/Nanoprocessing in Industrial Applications

“…Reproduced with permission. [ 129 ] Copyright 2021, American Chemical Society. d) 3D micro/nanofabrication based on mineral trioxide aggregate (MTA) composite resins by two‐photon polymerization (TPP) lithography and scanning electron microscopy images of various functional micro/nanostructures including a micropyramid, arrays of microcapacitors, a microcoil inductor, a spiral‐like photonic crystal, and a microgear.…”

“…[126,127] Hybrid LBM methods, one of the future development directions, can help precisely control the microstructuring of materials ranging from fluorescent polymeric structures to superhydrophobic surfaces, composite resins, and shapememory polymers, thus promoting novel applications such as micro-supercapacitors, solar cell devices, integrated photonics, anticounterfeiting devices, and optical encryption devices. [128][129][130]…”

“…c) Schematic of the setup used for fs laser processing and reconfiguration of fabricated holograms on a heat-shrinkable PO film for holographic multiplexing. Reproduced with permission [129]. Copyright 2021, American Chemical Society.…”

Dynamic Augmented Reality Display by Layer‐Folded Metasurface via Electrical‐Driven Liquid Crystal

“…On the other hand, in the evolutionary trend toward the intelligent optical device, dynamic tunability is also essential to metadevice functionality. Various dynamic mechanisms, including electrical [11,[33][34][35][36][37] /thermal [38][39][40] /mechanical [41] /optical tuning [42] schemes, have been investigated to exhibit switchable optical performance. Among the main active modulation methods, electrical-driven liquid crystal (LC) [43][44][45] is of tremendous promise to integrate with meta-device and practically exhibit tunable functionality due to its stability, easy-accessibility, and fast modulation rate.…”