Effect of Polyvinylidene Fluoride Hollow Fiber Membranes on Mass Transfer of Samarium

The influence of swelling and stripping acidity on the mass transfer coefficient based on water phase and the inner diameters of membranes were studied with P507-HCl-Sm as working system in the two different kinds of hollow fiber membranes. Effects of extractant concentration, H+ concentration in aqueous phase and Sm3+ concentration on extraction rate were discussed and the corresponding reaction series were obtained. According to the investigations on the interfacial kinetics, the reaction kinetics equation and reaction rate constant were obtained.

An Effective Thermal Splicing Method to Join Fluoride and Silica Fibers for a High Power Regime

A repeatable and simple thermal splicing method for low loss splice between fluoride and silica fibers is presented. The minimum splicing loss of 0.58 dB is achieved experimentally with this approach, Meanwhile, the power capacity of this splicing joint is also tested with a high power fiber laser. The maximum input power is up to 15 W, only limited by the available power of the laser source. To the best of our knowledge, this is the first report on thermal splicing between fluoride and silica fibers operating in a high power regime without any complicated ion-assisted deposition process.

Recent Progresses on Passively Switched Mid-Infrared Fiber Lasers at 3 μm

We present the recent research progress of our group on mid-infrared pulsed fiber lasers at 3μm by passive switching. Three different kinds of saturable absorbers including semiconductor saturable absorber （SESAM）, Fe2＋：ZnSe crystal, topological insulator （TI） were used to perform the pulse generation, respectively. The temporal regimes of mode locking, Q-switching and Q-switching induced gain switching were gained. Some relative discussions and prospective efforts are proposed at the end of this paper.

Mid-Infrared Raman Fiber Lasers

As mid-infrared （MIR） lasers show numerous applications in the field of defense, medical, materials processing, and optical communications. Investigation on MIR Raman fiber lasers （RFL） increasingly becomes a hot topic. Compared with traditional silica fiber, fluoride and chalcogenide glass fibers possess higher nonlinear coefficients and excellent MIR transmittances. In this article, the latest development of the MIR RFL using fluoride and chalcogenide glass fibers as gain media are introduced, respectively. This review article mainly focuses on the development of MIR RFLs in aspects of output wavelength, output power and optical efficiency. The prospect of MIR RFLs is also discussed.

High-power mid-infrared femtosecond master oscillator power amplifier Er:ZBLAN fiber laser system

High-power femtosecond mid-infrared(MIR)lasers are of vast importance to both fundamental research and applications.We report a high-power femtosecond master oscillator power amplifier laser system consisting of a singlemode Er:ZBLAN fiber mode-locked oscillator and pre-amplifier followed by a large-mode-area Er:ZBLAN fiber main amplifier.The main amplifier is actively cooled and bidirectionally pumped at 976 nm,generating a slope efficiency of 26.9%.Pulses of 8.12 W,148 fs at 2.8μm with a repetition rate of 69.65 MHz are achieved.To the best of our knowledge,this is the highest average power ever achieved from a femtosecond MIR laser source.Such a compact ultrafast laser system is promising for a wide range of applications,such as medical surgery and material processing.

Biomimetic Modification of Super-wetting Electrospun Poly(vinylidene fluoride)Porous Fibers with Organic Dyes and Heavy Metal Ions Adsorption,Oil/Water Separation,and Sterilization Performances Toward Wastewater Treatment

Polymeric membranes with the integration of various functional performances toward wastewater treatment are urgently required.However,most of the polymeric membranes only exhibit a single function of highly efficiently removing one kind of pollutants.In this work,a biomimetic modification method was introduced to tailor the chemical and topological structure of the porous poly(vinylidene fluoride)(PVDF)fibers prepared by electrospinning.The polydopamine(PDA)nanoparticles were homogeneously introduced onto the surface of PVDF porous fibers via precisely tailoring the concentration of dopamine,which endowed the fibers with more polar groups and bigger roughness but did not destroy the crystalline structures.The fibrous membranes exhibited switchable superhydrophilicity and superlipophilicity characteristics,excellent adsorption abilities toward organic dyes,heavy metal ions and oils.The highest adsorption capacities achieved 917.4 mg/g toward methylene blue(MB),42.6 mg/g toward Cr(VI)and 74.6 g/g toward silicone oil,respectively.Specifically,the membrane could rapidly remove the trace MB when water flowed through the membrane.The membrane also exhibited excellent sterilization performances,and the bacterial eliminating rate achieved 99.9%for the E.coli and S.aureus.The excellent light-to-heat conversion ability endowed the membrane with the selfheating ability,furtherly intensifying the wastewater treatment efficiency.This work confirms that the PDA nanoparticles-decorated PVDF porous fibers might be the new generation adsorbents used in wastewater treatment.

Mode-locked fiber laser of 3.5 μm using a single-walled carbon nanotube saturable absorber mirror

We report on a mid-infrared fiber laser that uses a single-walled carbon nanotube saturable absorber mirror to realize the mode-locking operation.The laser generates 3.5 μm ultra-short pulses from an erbium-doped fluoride fiber by utilizing a dual-wavelength pumping scheme.Stable mode-locking is achieved at the 3.5 μm band with a repetition rate of 25.2 MHz.The maximum average power acquired from the laser in the mode-locking regime is 25 mW.The experimental results indicate that the carbon nanotube is an effective saturable absorber for mode-locking in the mid-infrared spectral region.