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In this work, we experimentally demonstrate a high-performance laser-driven flyer (LDF) by introducing a perfect absorber in the ablation layer to improve the energy utilization efficiency, where the perfect absorber is composed of a layer of silver nano-triangular array, a dielectric layer, and a layer of silver film. The perfect absorber was realized by the simple and low-cost colloid lithography technique, and the maximal absorbance can reach to about 95% at 1064 nm under an optimization condition. The in-depth electromagnetic simulation indicates that the perfect absorber can greatly improve the energy absorbance in the ablation layer at the beginning of laser illumination, and thus the temperature and pressure of the subsequently generated plasma. In experiment, this improved plasma was used to launch a 25 µm thick Al flyer, and the flyer velocity was measured using a photonic Doppler velocimetry. A maximum speed of about 2140 m s − 1 was achieved in experiment, which is about 1.3 times larger than that (1650 m s − 1 ) of pure Al foil flyers. The extracted transient accelerated speed indicates that the absorber improved LDF owns higher accelerated speed at the beginning 20 ns, especially for the beginning 5 ns. The striking experiment indicates that the flyers formed in the improved LDF own a larger averaged striking depth, and some flyers give a striking depth in 80 µm that is twice larger than that formed in the normal LDF. The electromagnetic properties of the perfect absorber, the transient speed of flyer, and the striking morphology have been systematically investigated.

In this paper, the influence of Al/Ni reactive multilayer films on laser ablation induced plasma process is investigated. Laser ablation of single Ni layer and Al/Ni RMFs was performed by nanosecond pulsed laser beam with 1064 ​nm wavelength. The characterization methods were applied for researching the structure and chemical composition with transmission electron microscopy, X-ray photoelectron spectroscopy, and atom probe tomography. The effects of the Al/Ni RMFs on the plasma properties were then systematically investigated in terms of the electron temperature, density and ionization. Meanwhile, measurements of the plasma expansion velocity were performed using ICCD system. The results exhibit improved plasma behaviors with high electron temperature, fast expansion velocity and violent ablation phenomenon of Al/Ni RMFs in comparison with the Ni film, which is significant for broadening the potentials in military applications.

Laser-driven flyers (LDFs), which can drive metal particles to ultra-high speeds by feeding high-power laser, have been widely used in many fields, such as ignition, space debris simulation, and dynamic high-pressure physics. However, the low energy-utilization efficiency of the ablating layer hinders the development of LDF devices towards low power consumption and miniaturization. Herein, we design and experimentally demonstrate a high-performance LDF based on the refractory metamaterial perfect absorber (RMPA). The RMPA consists by a layer of TiN nano-triangular array, a dielectric layer and a layer of TiN thin film, and is realized by combing the vacuum electron beam deposition and colloid-sphere self-assembled techniques. RMPA can greatly improve the absorptivity of the ablating layer to about 95%, which is comparable to the metal absorbers, but obviously larger than that of the normal Al foil (∼10%). This high-performance RMPA brings a maximum electron temperature of ∼7500 K at ∼0.5 µs and a maximum electron density of ∼1.04 × 1016 cm-3 at ∼1 µs, which are higher than that the LDFs based on normal Al foil and metal absorbers due to the robust structure of RMPA under high-temperature. The final speed of the RMPA-improved LDFs reaches to about 1920 m/s measured by the photonic Doppler velocimetry system, which is about 1.32 times larger than the Ag and Au absorber-improved LDFs, and about 1.74times larger than the normal Al foil LDFs under the same condition. This highest speed unambiguously brings a deepest hole on the Teflon slab surface during the impact experiments. The electromagnetic properties of RMPA, transient speed and accelerated speed, transient electron temperature and density have been systematically investigated in this work.

Three kinds of Al flyer plates with different nanostructured absorption layers were in situ prepared by a direct laser writing technology to improve the energy conversion efficiency in a laser-driven flyer assembly. Microstructures, light absorption, and flyer velocity in the acceleration chamber were investigated. The reflectance for the flyers at 1064-nm wavelength can be reduced from 81.3 to 9.8% by the nanostructured absorption layer. The terminal velocity of a 50-μm-thick Al flyer irradiated by a 60-mJ laser pulse is 831 m/s, while the velocity of the flyer with an in situ-fabricated nano-absorption layer reaches up to 1113 m/s at the same condition. Resultantly, the energy conversion efficiency of the flyer with a nanostructure absorption layer can reach as high as 1.99 times that of the Al flyer. Therefore, the nanostructured absorption layer in situ prepared on the surface of a flyer provides a new method to significantly improve the energy conversion efficiency of a laser-driven flyer.

Three kinds of Al flyer plates with different nanostructured absorption layers were in-situ prepared by a direct laser writing technology to improve the energy conversion efficiency in a laser-driven flyer assembly. Microstructures, light absorption, flyer velocity in the acceleration chamber were investigated. The reflectance for the flyers at 1064 nm wavelength can be reduced from about 80% to 9.6% by the nanostructured absorption layer. The terminal velocity of a 50 μm thick Al flyer irradiated by a 60mJ laser pulse is 831 m/s, while the velocity of the flyer with an in-situ fabricated nano-absorption layer reaches up to 1113 m/s at the same condition. Resultantly, the energy conversion efficiency of the flyer with nanostructure absorption layer can reach as high as 1.99 times that of the Al flyer. Therefore, the nanostructured absorption layer in-situ prepared on the surface of a flyer provides a new method to significantly improve the energy conversion efficiency of a laser-driven flyer.

In this work, we demonstrate a kind of new standing wave modes of carrying space beat-frequency effect in an optimized nanopillar array, which can greatly reshape the electric filed distribution and result in high-quality biosensors. The in-depth theoretical research reveals that the mismatch of SPP wave vector and the light wave vector of high-order modes in medium is the crucial factors. The coupling distance, the SPP propagation distance, and the structure parameters also have been systematically investigated. Our results enrich the standing wave modes in nanostructures and give new insights into the fundamental understanding of the standing wave modes.

The dramatic temperature rise of energetic materials when using only millisecond pulses of light is very important for photothermic ignition. Here we demonstrate a free-standing laser energy converter based on energetic graphene oxide, which exhibited an ultrafast and large temperature rise from 21 to 670 °C within 8.7 ms during the irradiation of laser pulses, while the temperature of the graphene-based laser energy converter can only be raised from 21 to 170 °C under the same conditions. The reason for the unexpected and much larger temperature rise of energetic graphene oxide than graphene was studied by laser scanning microscopy and thermal analysis, which indicated that the temperature rise is strongly dependent on the content of oxygen-containing groups in energetic graphene oxide. The combination process of focused ion beam and transmission electron microscope characterization was utilized for the direct observation of the layer-stacked structure in free-standing graphene oxide and graphene membranes. Furthermore, the initiating energy of laser initiators was 40% decreased by adding a thin layer of the free-standing laser energy converter based on energetic graphene oxide, which shows great potential for developing photothermic ignition with low initiating energy.

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As a safe, reliable, and strongly electromagnetic resistant initiation method, laser initiation shows great promise in military blasting applications. Many obstacles exist when delivering a high-energy laser through optical fibers, directly influencing the energetic explosives under low-initiation conditions. Herein, we developed silver nanoplates as a laser energy absorber to reduce the laser initiation threshold and delay time. During the growth process of the silver seed nanoplates, mechanical disturbance was applied to provoke the nanoplates to develop more internal hotspots. Meanwhile, in ultraviolet visible near-infrared (UV–VIS-NIR) testing, the absorption peak was regulated to 808 nm by tailoring the size of the nanoplates. Results showed that the maximum temperature of the cracking nanoplates could reach 100 °C within 10 s, under the irradiation of an 808 nm diode laser at a power density of 1 W·cm−2. Through their use as a laser energy absorber, the silver nanoplates can effectively reduce the initiation threshold of cyclotrimethy lenetrinitramine (RDX) by 58.33% and reduce the delay time of B/KNO3 by 51.00%. This result provides potential applications for initiation energetic explosives at low laser energy.

MgAl hydride films with different hydrogen contents were fabricated in Ar and H2 mixed atmosphere using magnetron sputtering. Neutron reflectometry was performed to measure hydrogen contents, which indicated that up to 11atom% hydrogen was absorbed into MgAl. The MgAl hydride films were irradiated using pulsed lasers and the electron temperature and density of the generated plasma was measured. Results showed the electron temperature and density at delay time of 1μs were 7330 K, 7.9 × 1015 cm−3 and 8044 K, 9.0 × 1015 cm−3 for MgAl hydride films with 5atom% and 11atom% hydrogen, respectively. For comparison, the electron temperature and density for pure MgAl film were 5634 K and 6.9 × 1015 cm−3. Obviously, the electron temperature and density increases with the hydrogen content. Subsequently, the conversion ratio of the shock wave energy to the incident pulse energy were analyzed by investigating plasma induced shock wave evolution. The conversion ratio for MgAl hydride films with 5atom% and 11atom% hydrogen was 19.2% and 28.6%, which was 1.2 and 1.8 times of that for the MgAl film. Therefore, the MgAl hydride film promised to be a new class of material capable of promoting the plasma generation of the laser-driven flyers.

Light-ignited combustions have been proposed for a variety of industrial and scientific applications. They suffer, however, from ultrahigh light ignition thresholds and poor self-propagating combustion of typical high-energy density materials, e.g., 2,4,6,8,10,12-(hexanitrohexaaza)cyclododecane (CL-20). Here, reported is that both light ignition and combustion performance of CL-20 are greatly enhanced by embedding e-CL-20 particles in a graphene oxide (GO) matrix. The GO matrix yields a drastic temperature rise that is sufficient to trigger the combustion of GO/CL-20 under low laser irradiation (35.6 mJ) with only 6 wt% of GO. The domino-like reduction-combustion of the GO matrix can serve as a relay and deliver the decomposition-combustion of CL-20 to its neighbor sites, forming a relay-domino-like reaction. In particular, a synergistic reaction between GO and CL-20 occurrs, facilitating more energy release of the GO/CL-20 composite. The novel relay-domino-like reaction coupled with the synergistic reaction of CL-20 and GO results in a deflagration of the material, which generates a high-temperature pulse (HTP) that can be guided to produce advanced functional materials. As a proof of concept, a bi-layered photothermal membrane is prepared by HTP treatment in an extremely simple and fast way, which can serve as a model architecture for efficient interfacial water evaporation.

Aluminum nanoparticles were added into cyclotrimethylenetrinitramine (RDX) to enhance the laser absorption and lower the initiation energy of pulse laser. Polyvinyl acetate (PVA), polyvinyl butyral (PVB), and fluororubber (F2314) were added into RDX as binders to prepare the RDX-based composite explosives with desirable mechanical behavior. The influence of aluminum nanoparticles and binders on the light absorption, thermal behavior, laser initiation energy and the electron temperature in aluminum plasma were investigated using reflectance spectroscopy, differential scanning calorimetry, laser initiation and laser-induced breakdown spectroscopy. Results showed that the addition of aluminum nanoparticles could prominently lower the laser initiation energy of the RDX-based explosives. The RDX doped with 2.0% aluminum nanoparticles could be reliably initiated with 1.5 J/cm2 laser energy (1064 nm, 8 ns). The laser initiation energy increased to 1.7, 2.4 and 2.9 J/cm2 with the additions of 0.5%, 1.0% and 2.0% F2314 binders, respectively. When the addition of PVA and PVB increased to 2.0%, the RDX-based explosives couldn’t be initiated by pulse laser. When the pulse laser radiated on the surface of the RDX-based composite explosives, the aluminum nanoparticles absorbed the laser energy and were heated to high temperature to initiate the explosives. The addition of binders can provide desirable mechanical behavior, but the laser initiation energy increased because the heat transmission from aluminum nanoparticles to RDX was hindered.

As the core feature of Chinese art, imagery runs through the whole process of art development. This paper discusses the inheritance and innovation of traditional imagery style, the content of sculpture art in the process of modernization, and puts forward personal understanding of the development, innovation and transformation of contemporary sculpture. The contemporary sculpture art is transforming from traditional mysterious imagery to clear and orderly style, this process is an innovation and transformation based on inheriting traditional art style.