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Summary: Femtosecond laser direct writing (FsLDW) has been established as a nano-enabler to solve problems that are otherwise not possible in diversified scientific and industrial fields, because of its unique three-dimensional processing capability, arbitrary-shape designability, and high fabricating accuracy up to tens of nanometers, far beyond the optical diffraction limit. We briefly review the underlying mechanisms for achievement of the superhigh fabrication spatial resolution and surface smoothness, and then discuss the rule and photochemical strategies that are currently exploited for FsLDW. Finally, applications of the delicate nanoprototyping approach in microelectronics, micromechanics, microoptics and microfluidics are introduced. [ABSTRACT FROM AUTHOR]

Abstract: Large size single transient cavitation bubbles of maximum diameters up to 2.6 cm have been generated in water by the “tube arrest” method. The light emissions with light pulses width less than 750 ps during the collapse of the bubbles would be the multibubble sonoluminescence as shown by the analyses of high-speed photograph and light emission data. [Copyright &y& Elsevier]

Soft robots enabling controllable movement in a predicable manner have attracted enormous research interests. However, current researches on soft robots are mainly limited to single actuation mode, and thus complex and multidimensional motility is significantly limited. Here, we propose and demonstrate for the first time a multi-field-coupling energy conversion strategy for flexible manipulation of soft robots, by which 3D-positioning, rotating, levitating, capturing and releasing of a small object by a smart claw are synergistically realized via magnetic, ultrasonic, humidity and light fields. The essence of the strategy is coupling design of the robot compositional materials that can convert energy from different fields into efficient mechanical works. As a typical example, we developed a magnetic-field-assisted gradient assembly method for preparing asymmetric Fe 3 O 4 nanoparticles (NPs) and graphene oxide (GO) composite film. The asymmetric distribution of Fe 3 O 4 NPs in GO leads to an reasonable mechanical stiffness and alters the water adsorption capability of the two sides, which not only imparts multi-responsiveness but also suitably addresses the problem of interlayer detachment in the case of bimorph actuators. The robust soft robots demonstrate good durability, revealing great potential for developing advanced robotic systems that permit direct conversion of multi-field energies to mechanical works. Image 1 • The strategy of multi-field-coupling energy conversion has been adopted for manipulating soft robots. • External magnetic field assists the assembly of Fe 3 O 4 NPs and GO sheets into an asymmetric composite film. • Magnetic, ultrasonic, humidity and light energies can be synergistically coupled with the robot. • A smart claw capable of flexible motility and multi-form deformation is demonstrated. [ABSTRACT FROM AUTHOR]

GeSbTe alloys have the ability of rapidly transforming between amorphous and crystalline phases. Therefore, they can be used in the non-volatile phase change memory. Recently, a vacancy-ordered cubic Ge 2 Sb 2 Te 5 ( VOC GST) phase change material where the vacancies are highly ordered in the (111) plane, has been experimentally demonstrated by STEM. However, studies are mainly on the structural characterization, rather than on the phase change behavior and possible applications of the VOC GST. Here, using first-principles molecular dynamic simulations, we study the melt-quenched amorphization process and its possible applications. We find that the VOC GST exhibits a quasi-two-dimensional amorphization process that is triggered by the diffusion of Ge atoms but not others. A partial amorphous ( P-amor ) phase is obtained, which can act as an intermediate state between the pure amorphous and pure crystalline phases for possible ternary-state data storage. [ABSTRACT FROM AUTHOR]

Abstract: Two-beam-laser interference was used for the simultaneous reduction, patterning and nanostructuring of graphene oxide on flexible polyethylene terephthalate substrates for the production of a high performance humidity sensing device. Hierarchical graphene nanostructures were formed after laser interference treatment of graphene oxide, which holds great promise for gaseous molecular adsorption, and thereby significantly increases their sensing performance. By tuning the laser power, the content of oxygen functional groups, could be changed within a certain range, which contributes not only controllable conductivity but also tunable response/recovery time of the humidity sensor due to the interaction between water molecules and oxygen functional groups on the graphene oxide sheets. The laser interference processing of graphene oxide films is a mask-free, surfactant-free and large-area approach to the production of hierarchical graphene micro-nanostructures, and thus shows great potential for fabrication of future graphene-based microdevices. [Copyright &y& Elsevier]

• Recent advances in laser-induced color centers in different crystals are comprehensively reviewed, including diamond, silicon carbide, alkali halide crystals and others. • Cutting-edge applications of laser-induced color centers are introduced. • Current challenges and future perspective of this field have been discussed. • Cited figures are adapted carefully for a better understanding for readers. Color centers are widely used in quantum information, quantum sensing, micro-nano optics and other relevant fields. In addition to the traditional ways that can generate color centers, for instance, ion beam implantation, direct laser writing (DLW) technology has recently emerged as an appealing alternative to induce color centers because it enables true three-dimensional and high precision machining. Particularly, DLW can induce color centers near/on the surface or inside the crystals with a homogeneous and pure surrounding environment, which permits subsequent integration with other components. In this paper, the recent advances in laser-induced color centers in different crystals are comprehensively reviewed, including diamond, silicon carbide, alkali halide crystals and others. Meanwhile, cutting-edge applications of laser-induced color centers are introduced. Lastly, current challenges and future perspective of this field have been discussed. [ABSTRACT FROM AUTHOR]