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A two-channel ytterbium-doped fiber amplifier system with active phase-locking reaches a differential phase noise of only 40 mrad (X/160) at 200-W channel power. Frequencies above 30 Hz did not require noise suppression, thus simplifying advanced beam-shaping through coherent beam combination.

A high-power 1.9-µm Tm3+-doped silica fiber laser generates 7.3-dB of gain at 2.3 µm when cladding- pumped with 207 W of power at 793 nm. We attribute the 2.3-µm gain to the transition 3H4 → 3H5 of Tm3+.

Liquid metal (LM) bioelectronics find widespread uses in healthcare devices and medical implants. However, the current LM‐based electrodes suffer from achieving a combination of features including stable conductivity, high tissue adhesion, stability, good biocompatibility, degradability, and recyclability. In this work, a stable LM electrode is prepared with an extremely high adhesion strength (8.9 MPa), which is tunable in a wide range by introducing an adhesive ureidopyrimidinone (UPy)‐based polymer to harvest the abovementioned properties. With the help of dynamic LM particle‐polymer interactions in the polymer matrix, LMs can not only enhance the adhesion properties but also form a percolated network at a low LM loading (38 vol%) to achieve a high conductance stability (R/R0 = 0.76 at 100% strain). The high adhesion strength provides a highly stable electrical connection with rigid components with a high stretchability of 1154% when mounting a resistor, while a relatively low adhesion makes it a comfortable wounded skin‐interfaced electrode for accelerating wound healing. Taking advantage of their tunable surface adhesion and biocompatibility, the as‐prepared LM electrodes provide a more reliable and friendly approach to the development of healthcare devices. [ABSTRACT FROM AUTHOR]

Here, a superhydrophobic and catalytically active metal–organic framework (MOF) coating is reported by coordination‐driven assembly of MOF nanoparticles and a catechol‐functionalized polysiloxane polymer. This MOF coating can be fabricated by casting MOF‐polymer precursor onto diverse substrates with varied coating techniques, for example, spray coating, bar coating, and dip coating. The catechol‐functionalized polymer can not only coordinate to the open metal sites on MOF surface which enables the surface functionalization and assembly of MOF nanoparticles, but also allow non‐covalent interactions with casting substrates—thus improving the substrate adhesion of the MOF coating. With the well‐preserved porosity and surface hydrophobicity, the MOF coating demonstrates superhydrophobicity as well as improved catalytic activity toward the Knoevenagel condensation at room temperature. Such coordination‐driven assembly approach can be extended to a range of MOF systems for preparing highly functional composite materials toward various applications. [ABSTRACT FROM AUTHOR]

Humidity-based power generation that converts internal energy of water molecules into electricity is an emerging approach for harvesting clean energy from nature. Here it is proposed that intrinsic gradient within a humidity field near sweating surfaces, such as rivers, soil, or animal skin, is a promising power resource when integrated with liquid-infused nanofluidics. Specifically, capillary-stabilized ionic liquid (IL, Omim + Cl - ) film is exposed to the above humidity field to create a sustained transmembrane water-content difference, which enables asymmetric ion-diffusion across the nanoconfined fluidics, facilitating long-term electricity generation with the power density of ≈12.11 µW cm -2 . This high record is attributed to the nanoconfined IL that integrates van der Waals and electrostatic interactions to block movement of Omim + clusters while allowing for directional diffusion of moisture-liberated Cl + . This humidity gradient triggers large ion-diffusion flux for power generation indicates great potential of sweating surfaces considering that most of the earth is covered by water or soil., (© 2021 Wiley-VCH GmbH.)