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Abstract Flexible optoelectronic devices have attracted considerable attention due to their low weight, portability, and ease of integration with other devices. However, major issues still exist: they are subject to repeated stresses, which often leads to damage; and the current fabrication methods such as photolithography and nano-imprint lithography can be very time-consuming or costly. This work aims to develop a novel cost-effective and time-efficient laser metasurface fabrication (LMF) technique for production of flexible optoelectronic devices. The experimental results have shown that the laser patterned flexible surfaces exhibit high visible transmittance, low sheet resistance, and extraordinary mechanical durability under repeated bending cycles. The laser patterned flexible surfaces have also demonstrated the potential to be utilized as heaters, which renders them new de-icing or de-fogging applications. This innovative laser patterning method will provide a new avenue for fabrication of multifunctional optoelectronic devices. 

Abstract Terahertz (THz) imaging has attracted much attention within the past decade as an emerging nondestructive evaluation technique. In this paper, we present a novel Laser-based Metamaterial Fabrication (LMF) process for high-throughput fabrication of transparent conducting surfaces on dielectric substrates such as glass, quartz and polymers to achieve tunable THz bandpass characteristics. The LMF process comprises two steps: (1) applying ultrathin-film metal deposition, with a typical thickness of 10 nm, on the dielectric substrate; (2) creating a ~100-micron feature pattern on the metal film using nanosecond pulsed laser ablation. Our results demonstrate the use of laser-textured ultra-thin film with newly integrated functional capabilities: (a) highly conductive with ~20 Ω/sq sheet resistance, (b) optically transparent with ~70% transmittance within visible spectrum, and (c) tunable bandpass filtering effect in the THz frequency range. A numerical analysis is performed to help determine the fundamental mechanism of THz bandpass filtering for the LMF-built samples. The scientific findings from this work render an economical and scalable manufacturing technique capable of treating large surface area for multi-functional metamaterials. 

Abstract Development of terahertz (THz) sources, detectors, and optical components has been an active area of research across the globe. The interest in THz optoelectronics is driven by the various applications they have enabled, such as ultrawide‐band communication systems, air‐ and space‐borne astronomy, atmospheric monitoring, small‐scale radar, airport security scanners, ultrafast nanodevices, and biomedical imaging and sensing. Here, the aim is to provide a comprehensive review of THz bandpass metamaterials focusing on several areas. First, the design fundamentals and geometrical patterns of THz bandpass metamaterials are summarized. Second, fabrication methods of THz bandpass metamaterials are reviewed, including typical micro‐ and nanofabrication techniques and laser micromachining techniques. More importantly, different engineering methods are reviewed for tuning and modulation of the THz transmission resonance for these metamaterials. Both passive and active modulation methods are included in this discussion; the passive method involves changes in the geometrical pattern of the filter material, and the active method performs in situ modulation of properties by applying an external physical field. Finally, the potential applications and prospects for future research of THz bandpass metamaterials are discussed.