Perfect metamaterial absorber improved laser-driven flyer

Laser driven flyer (LDF) can drive small particles to ultrahigh speed (several km/s) by feeding pulse laser light, and exhibits giant application prospect in both of the civilian and military regions, such as the ignition of missile and spacecraft and dynamic high-pressure loading. In this work, we demonstrate a high-performance LDF by using the perfect metamaterial absorber (PMA) to improve the energy utilization efficiency of light. The designed Ag nanopillar array in anodic aluminum oxide templates (APA-AAO) were skillfully fabricated in-situ on the flyer layer surface, which can greatly reduce the reflectivity from 93% of the pure Al foil flyers to about 5% of the APA-AAO enhanced flyers. Our systematically transient analysis reveals that this ultralow reflectivity, together with the well-formed metal structure on Al foil, greatly improve both of the electron temperature and sustaining time of plasma formed in the ablating layer, and further enhances the acceleration process at both of the initial detonation wave generation stage (0–10 ns) and the following thermal expansion stage (10–200 ns). The final speed of the flyer generated in the PMA-enhanced LDF approach to 1730 m/s, which is about 1.4 times larger than that (1250 m/s) of the pure Al foil flyers. The transient electron temperature, transient flyer shadowgraph, plasma sustaining time, velocity, and accelerated velocity have been investigated systematically in this work. This PMA enhanced LDF provides an effective method for obtaining high-speed microparticles, and opens up a new perspective and guidance for designing high-performance LDF.

Dual functionality metamaterial enables ultra-compact, highly sensitive uncooled infrared sensor

Cointegration and coupling a perfect metamaterial absorber (PMA) together with a film bulk acoustic wave resonator (FBAR) in a monolithic fashion is introduced for the purpose of producing ultracompact uncooled infrared sensors of high sensitivity. An optimized ultrathin multilayer stack was implemented to realize the proposed device. It is experimentally demonstrated that the resonance frequency of the FBAR can be used efficiently as a sensor output as it downshifts linearly with the intensity of the incident infrared irradiation. The resulting sensor also achieves a high absorption of 88% for an infrared spectrum centered at a wavelength of 8.2 μm. The structure is compact and can be easily integrated on a CMOS-compatible chip since both the FBAR and PMA utilize and share the same stack of metal and dielectric layers.