Antimonene, a new type of mono/few-layer two-dimensional (2D) mono-elemental material purely consisting of antimony similar as graphene and phosphorene, has been theoretically predicted with excellent optical response and enhanced stability. Herein, we experimentally investigated the broadband nonlinear optical response of highly stable few-layer antimonene (FLA) by performing an open-aperture Z-scan laser measurement. Thanks to the direct bandgap and resonant absorption at the telecommunication band, we demonstrated the feasibility of FLA-decorated microfiber not only as an optical saturable absorber for ultrafast photonics operation, but also as a stable all-optical pulse thresholder that can effectively suppress the transmission noise, boost the signal-to-noise ratio (SNR), and reshape the deteriorated input signal. Our findings, as the first prototypic device of absorption of antimonene, might facilitate the development of antimonene-based optical communication technologies towards high stability and practical applications in the future.
2D titanium disulfide (TiS2) is recently found to have strong light absorption properties from visible to infrared (IR) region. This feature is highly attractive for applications in nonlinear photonics; however, the mechanism of broadband light–matter interaction is yet to be determined and nonlinear photonic devices are not developed. Here, for the first time, the experimental evidence supporting the mechanism of the broadband nonlinear photoresponse in ultrathin TiS2 nanosheets ranging from 400 nm to 1390 nm is reported through laser Z‐scan measurements. High‐performance nonlinear photonic devices operating in the telecommunication band are also demonstrated. A novel saturable absorber (SA) device is successfully fabricated based on a 2D TiS2‐decorated fiber, which exhibits outstanding ultrashort pulse generation performance with pulse duration of ≈1.04 ps centered at 1569.5 nm. Furthermore, as a stable all‐optical thresholding component, the device can effectively attenuate noise and boost the signal‐to‐noise ratio of the pulse from 1.90 to 10.68 dB. The findings indicate that TiS2‐based SA devices can be developed into excellent highly nonlinear photonic devices, which may advance the development of TiS2‐based optical communication technologies in the future.
Bismuthene has attracted a great deal of attention because of its unique electronic and optical properties. However, there are few reported applications of bismuthene in nonlinear optical applications. In this research, a dissipative soliton ytterbium-doped mode-locked fiber laser at 1 μm regime with a bismuthene saturable absorber (SA) by using evanescent field interaction for the first time is demonstrated. The nonlinear optical absorption of microfiber-based bismuthene SA is shown experimentally by using a homemade ultrafast fiber laser, whose saturation intensity and modulation depth are about 13 MW cm-2 and 2.2%, respectively. Relying on the excellent nonlinear optical property of the bismuthene SA, the typical dissipative solitons with a repetition rate of 21.74 MHz are generated at a center wavelength of 1034.4 nm. The time-bandwidth product of the pulse is about 23.07 with a pulse width of 30.25 ps. The results demonstrate that bismuthene is a good candidate for application in a 1 μm wave-breaking-free mode-locked fiber laser and nonlinear photonic components.
Phosphorene, mono/few‐layered black phosphorous with advantages of tunable energy bandgaps and strong light–matter interaction, is fabricated by electrochemical intercalation with large area (≈3 µm) and controllable thickness (mainly four layers). Thanks to the direct gap and resonant absorption of four‐layer phosphorene at the telecommunication band, all‐optical thresholding and optical modulation are demonstrated for optical communications by using few‐layer phosphorene‐decorated microfibers. This device is experimentally verified as an efficient noise suppressor that can enhance the signal‐to‐noise ratio and reshape the deteriorated signal pulse, and also as an optical modulator that can switch the signal on/off by pumping light. The findings, as the first prototypic device of all‐optical thresholding and optical modulation, might facilitate the development of phosphorene‐based optical communication technologies.
The synthesized FL Se-doped compound shows enhanced optical saturable absorption and high electrical characterizations, which can be developed as an excellent candidate for photoelectric devices.
A giant magnetic-field-induced strain (MFIS) of −3100 ppm has been obtained in Heusler alloy Ni52Mn22.2Ga25.8 single crystal in the [001] direction at a temperature from 23 to 31 °C. This MFIS reaches saturation in an applied field about 6 kOe, and exhibits the same amplitude with an opposite sign while the field is perpendicular to the samples. According to a previous model, this MFIS associates with the twin boundary motion. The martensitic self-strain has been found to be 2%, implying a preferential orientation of martensite variants. Results related to the magnetic properties are discussed.
Two-dimensional (2D) white-light-emitting hybrid perovskites (WHPs) are promising active materials for single-component white-light-emitting diodes (WLEDs) driven by UV. However, the reported WHPs exhibit low quantum yields (≤9%) and low color rendering index (CRI) values less than 85, which does not satisfy the demand of solid-state lighting applications. In this work, we report a series of mixed-halide 2D layered WHPs (CHCHNH)PbBr Cl (0 < x < 4) obtained from the phenethylammonium cation. Unlike the reported WHPs including (CHCHNH)PbCl, the mixed-halide perovskites display morphology-dependent white emission for the different extents of self-absorption. Additionally, the amount of Br has a huge influence on the photophysical properties of mixed-halide WHPs. With the increasing content of Br, the quantum yields of WHPs increase gradually from 0.2 to 16.9%, accompanied by tunable color temperatures ranging from 4000 K ("warm" white light) to 7000 K ("cold" white light). When applied to the WLEDs, the mixed-halide perovskite powders exhibit tunable white electroluminescent emission with very high CRI of 87-91.
A large magnetic entropy change has been observed in an intermetallic compound LaFe10.6Si2.4. The maximum −ΔSM≈3.2 J/kg K was found at its Curie temperature, ∼242 K, upon a 2 T magnetic field change. Although the entropy change is slightly smaller than that of pure Gd metal, such Fe-rich compounds still appear to be very attractive candidates since (a) the raw materials are much cheaper than pure Gd metal; (b) the Curie temperature can be easily shifted by tuning the composition; (c) the materials are much more chemically stable than pure Gd metal.
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