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Photoacoustic laser streaming provides a versatile technique to manipulate liquids and their suspended objects with light. However, only gold was used in the initial demonstrations. In this work, we first demonstrate that laser streaming can be achieved with common non-plasmonic metals such as Fe and W by their ion implantations in transparent substrates. We then investigate the effects of ion dose, substrate material and thickness on the strength and duration of streaming. Finally, we vary laser pulse width, repetition rate and power to understand the observed threshold power for laser streaming. It is found that substrate thickness has a negligible effect on laser streaming down to 0.1 mm, glass and quartz produce much stronger streaming than sapphire because of their smaller thermal conductivity, while quartz exhibits the longest durability than glass and sapphire under the same laser intensity. Compared with Au, Fe and W with higher melting points show a longer lifetime although they require a higher laser intensity to achieve a similar speed of streaming. To generate a continuous laser streaming, the laser must have a minimum pulse repetition rate of 10 Hz and meet the minimum pulse width and energy to generate a transient vapor layer. This vapor layer enhances the generation of ultrasound waves, which are required for observable fluid jets. Principles of laser streaming and temperature simulation are used to explain these observations, and our study paves the way for further materials engineering and device design for strong and durable laser streaming. 

Abstract The discovery of photoacoustic laser streaming has opened up a new avenue to manipulate and drive fluids with light, but the necessity of an in situ “launch pad” has limited its utility in real‐world microfluidic applications due to both the size constraint and the complexity of fabrication. Here, it is demonstrated that 1) a versatile microfluidic pump can be materialized by using laser streaming from an optical fiber, and 2) laser streaming can be generated from a flat metal surface without any fabrication process. In the latter case, by focusing laser on the tip of a sewing needle tip, the needle can be turned into a micropump with controllable flow direction. Additionally, high‐speed imaging of the fluid motion and computational fluid dynamics simulations to confirm the photoacoustic principle of laser streaming are employed, and it is revealed that the streaming direction is determined by the direction of strongest intensity in the divergent ultrasound wavefront. Finally, the potential of laser streaming for microfluidic and optofluidic applications is demonstrated by successfully driving fluid inside a capillary tube. 

Abstract The integration of highly luminescent CsPbBr₃quantum dots on nanowire waveguides has enormous potential applications in nanophotonics, optical sensing, and quantum communications. On the other hand, CsPb₂Br₅nanowires have also attracted a lot of attention due to their unique water stability and controversial luminescent property. Here, the growth of CsPbBr₃nanocrystals on CsPb₂Br₅nanowires is reported first by simply immersing CsPbBr₃powder into pure water, CsPbBr_3−γ X_γ(X = Cl, I) nanocrystals on CsPb₂Br_5−γ X_γnanowires are then synthesized for tunable light sources. Systematic structure and morphology studies, including in situ monitoring, reveal that CsPbBr₃powder is first converted to CsPb₂Br₅microplatelets in water, followed by morphological transformation from CsPb₂Br₅microplatelets to nanowires, which is a kinetic dissolution–recrystallization process controlled by electrolytic dissociation and supersaturation of CsPb₂Br₅. CsPbBr₃nanocrystals are spontaneously formed on CsPb₂Br₅nanowires when nanowires are collected from the aqueous solution. Raman spectroscopy, combined photoluminescence, and SEM imaging confirm that the bright emission originates from CsPbBr_3−γ X_γnanocrystals while CsPb₂Br_5−γ X_γnanowires are transparent waveguides. The intimate integration of nanoscale light sources with a nanowire waveguide is demonstrated through the observation of the wave guiding of light from nanocrystals and Fabry–Perot interference modes of the nanowire cavity.