Metal−organic frameworks (MOF) or their derivatives have attracted much attention in recent years due to exciting properties such as high specific surface area, adjustable pore size, and easy functionalization, which makes them have unique advantages in the fields of catalysis, energy storage, optoelectronics, and so on. However, the study of them in the fields of nonlinear optics and ultrafast photonics is still in its early stage. Here, by annealing the MOF template, porous MOF-derived CuO octahedra are prepared and applied to the above fields. Experiments show that CuO octahedra possess an excellent nonlinear optical absorption capacity in the near-infrared band. When it is used as a saturable absorber (SA) to the fiber lasers, high order harmonic soliton molecules with a repetition frequency up to 238 MHz can be obtained that make sense for optical frequency combs and optical communication. Besides, the dynamic evolution of the harmonic soliton molecule is explored. This work pioneers the application of MOF-derived metal oxide polyhedra as SAs in fiber lasers and expands the application fields of MOF-based materials. Moreover, this kind of emerging microstructured polyhedral SA, prepared by the new method, provides researchers with a new choice beyond quantum dots, nanoparticles, and 2D nanosheets/nanofilms.

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A system for the launch of hypervelocity flyer plates has been developed and characterized. Laser-driven flyers were launched from the substrate backed aluminum-alumina-aluminum sandwiched films. A laser-induced plasma is used to drive flyers with typical thickness of 5.5 μm and diameters of less than 1 mm, to achieve velocities of a few km/s. These flyer plates have many applications, from micrometeorite simulation to laser ignition. The flyer plates considered here have up to three layers: an ablation layer, to form plasma; an insulating layer; and a final, thicker layer that forms the final flyer plates. This technique was developed aiming at improving the energy efficiency of the system. The kinetic energy of flyers launched with the additional layer was found to be enhanced by a factor of near 2 (up to 30%). The optical fiber delivery system governs the output spatial profile of the laser spot and power capacity. Moreover, a technique for coupling high-power laser pulses into an optical fiber has been developed. This fiber optic system has been successfully used to launch flyer plates, and the surface finishing quality of the fiber was found to be an important factor. Importantly, measurements of the flyer performance including the mean velocities and planarity were made by an optical time-of-arrival technique using an optical fiber array probe, demonstrating the good planarity of the flyer and the achievable average velocity of 1.7 km/s with approaching 1 mm diameter. Finally, the relationship between flyer velocities and incident laser pulses energy was also investigated.

High entropy alloys (HEAs) allow for attractive combinations of excellent mechanical and magnetic properties. The composition space of HEAs is enormous as it comprises multiple principal elements. Therefore, it is...