Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences
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Complete measurement of spatiotemporally complex multi-spatial-mode ultrashort pulses from multimode optical fibers using delay-scanned wavelength-multiplexed holography
No full textU. S. National Science Foundation (NSF) [ECCS-1307817, ECCS-1609808]; Georgia Research Alliance (GRA); China Scholarship Council (CSC)We introduce a simple delay-scanned complete spatiotemporal intensity-and-phase measurement technique based on wavelength-multiplexed holography to characterize long, complex pulses in space and time. We demonstrate it using pulses emerging from multi-mode fiber. This technique extends the temporal range and spectral resolution of the single-frame STRIPED FISH technique without using an otherwise-required expensive ultranarrow-bandpass filter. With this technique, we measured the complete intensity and phase of up to ten fiber modes from a multi-mode fiber (normalized frequency V approximate to 10) over a similar to 3ps time range. Spatiotemporal complexities such as intermodal delay, modal dispersion, and material dispersion were also intuitively displayed by the retrieved results. Agreement between the reconstructed color movies and the monitored time-averaged spatial profiles confirms the validity to this delay-scanned STRIPED FISH method
Design and calibration of hot-electron spectrometer array for angle-resolved measurement
No full textChinese Academy of Sciences [CXJJ-15S114]A hot-electron spectrometer array with two-dimensional distribution has been designed with a wide-angle range and high-energy resolution to measure the spatially resolved electron spectra for high-power-laser plasma interaction experiments. It consisted of 19 identical electron spectrometers set in three directions with an interval of 10 degrees. Each electron spectrometer was designed with a uniform magnetic field to detect electrons in the range from 20 to 500 keV. The spectrometers were calibrated using electrons from an accelerator. In an experiment, the spatially resolved electron energy spectra, which approximately had a Maxwell distribution, were obtained from an aluminum foil target irradiated by a 0.53-mu m m laser pulse. Published by AIP Publishing
CH3NH3PbI3 perovskite:poly(N-vinylcarbazole) blends for broadband optical limiting
No full textNational Natural Science Foundation of China [61378072, 61522510, 61675217]; Joint project of Ministry of Education and State Administration of Foreign Experts Affairs [TS2010HDLG024]; External Cooperation Program of BIC, CAS [181231KYSB20130007]; "Strategic Priority Research Program" of CAS [XDB16030700]; Key Research Program of Frontier Science, CAS [QYZDB-SSW-JSC041]As one of the most active areas in laser protection, organic/inorganic hybrid functional materials have been expected to play an extremely important role in the field of optical limiting. The optical limiting performance of the CH3NH3PbI3 perovskite: poly(N-vinylcarbazole) (weight ratio: 1 : 1) blends (hereafter abbreviated as CP) was experimentally studied in DMF and in a poly(methylmethlacrylate) (PMMA) matrix, respectively, using an open aperture Z-scan method. In contrast to the CP dispersed in DMF, which showed no apparent nonlinear optical (NLO) response at both 532 and 1064 nm, after annealing at 200 degrees C in N-2 for 30 min, a saturable absorption (SA) response was observed in the same DMF dispersion under the excitation of 532 nm laser. At 1064 nm, the annealed sample displayed different NLO responses: SA at the lower pulse energy and reverse saturable absorption (RSA) at the higher pulse energy. Both the 3 wt% and 6 wt% CP-doped PMMA composite films exhibited a typical RSA response, larger nonlinear absorption coefficient and superior optical limiting performance when compared to the same blends in DMF dispersion
High-Peak Power Passively Q-Switched 2-mu m Laser With MoS2 Saturable Absorber
No full textNational Natural Science Foundation of China [61378022, 61475088, 61475177]; Open Foundation of State Key laboratory of Crystal Material of Shandong University [KF1403]; Independent Innovation Foundation of Shandong University, IIFSDU [2013HW013]; Shandong University [2015WLJH38]The passive Q-switching characteristics of a diode-pumped Tm,Ho:YAP laser at 2 mu m based on a MoS2 saturable absorber (SA) is presented for the first time. Pulses as short as 435 ns under a repetition rate of about 55 kHz were generated at the incident pump power of 8.4 W, corresponding to the pulse peak power up to 11.3 W. This is, to the best of our knowledge, the highest pulse peak power, ever obtained from MoS2 based passively Q-switched 2-mu m lasers. The experimental results sufficiently validated the feasibility of MoS2 as SA for solid-state 2-mu m lasers
Perfectly transparent pore-free Nd3+-doped Sr9GdF21 polycrystalline ceramics elaborated from single-crystal ceramization
No full textNational Nature Science Foundation of China [61378069, 61405221]; Youth Innovation Promotion Association of the Chinese Academy of Sciences (CAS)An Nd3+-doped Sr9GdF21 (SGF) transparent pore-free polycrystalline ceramic is produced by the ceramization of single crystals. The average transmittance (TA) of the Nd3+-doped SGF ceramic (8-mm thick) is about 90.6% in the visible region and more than 92% in the near-IR region. The fracture toughness of the Nd3+-doped SGF ceramic is up to 1.28 MPa m(1/2), which is significantly higher than that of similar types of ceramics. Gd3+ ions, acting as both buffer ions and pinning ions, effectively improve the optical and mechanical properties of the SGF ceramic, implying that the sample is a promising candidate for high-power lasers. Moreover, the SGF ceramic shows a high mid- and far-infrared (up to 9 mu m) transmittance, low phonon energy, and high density (rho = 4.8466 g/cm(3)), which pave the way for a wide range of applications such as infrared windows, mid- and far-infrared lasers, scintillators, and in photonics. (C) 2017 Elsevier Ltd. All rights reserved
Sol-Gel-derived Mesoporous Calcium Aluminum Phosphate Bioactive Glasses with High Surface Area
No full text采用溶胶-凝胶法,在不使用模板剂的情况下制备出高比表面积的介孔CaO-Al_2O_3-P_2O_5生物活性玻璃(MBGs),用BET、XRD、DTA以及FTIR对MBGs的结构进行了表征, 并用生物模拟体液(SBF)在36.5℃对生物玻璃进行了体外活性测试, 测试时间为1 d、3 d、7 d和14 d。介孔玻璃的比表面积最高达到461.1 m~2/g, 随着CaO的含量从5mol%增加到30mol%, 介孔玻璃的比表面积呈降低趋势。用XRd和FTIR验证了材料的玻璃结构。然而, 在生物模拟体液(SBF)实验中, 当CaO摩尔含量达到20mol%时, 介孔玻璃表现出较高生物活性。这种特殊的高比表面积的介孔铝磷钙生物活性玻璃在生物医药方面有潜在的应用价值。本文的实验结果对优化生物玻璃的介孔结构和CaO含量来提升玻璃的生物活性有一定的指导意义。National Natural Science Foundation of China [1308491G00]High surface area mesoporous bioactive glasses (MBGs) with composition CaO-Al2O3-P2O5 were fabricated using a simple aqueous Sol-Gel method without any template. Structural characterization of the phosphate-based MBGs was performed by BET, DTA, XRD and FTIR, and MBGs' in vitro bioactivity was evaluated by soaking them in simulate body fluid for up to 15 d at 36.5 degrees C. The highest specific surface area is found to be 461.1 m(2)/g for the MBG with 5mol% CaO, and it decreased with increasing CaO content. And the glass structure for all the samples was confirmed by XRD and FTIR. However, the MBG with 20mol% CaO exhibits the best in vitro bioactivity using simulated body fluid among all samples. The unique combination of a higher specific surface area and relatively high CaO content enables mesoporous calcium aluminum phosphate bioactive glasses to be promising candidates for biomedical applications
Laser Direct Writing of Tree-Shaped Hierarchical Cones on a Superhydrophobic Film for High-Efficiency Water Collection
No full textNational Natural Science Foundation of China [U1613204, 10974037, 61505038, 61405223]; Program for Guangdong Introducing Innnovative and Entrepreneurial Team [2016ZT06G587]; "The Recruitment Program of Global Youth Experts of China" [K16251101]; National Key Research and Development Program of China [2016YFA0200403]; CAS Strategy Pilot Program [XDA 09020300]; Shenzhen Science and Technology Planning [JCYJ20160422142912923]Directional water collection has stimulated a great deal of interest because of its potential applications in the field of microfluidics, liquid transportation, fog harvesting, and so forth. There have been some bio or bioinspired structures for directional water collection, from one-dimensional spider silk to two-dimensional star-like patterns to three-dimensional Nepenthes alata. Here we present a simple way for the accurate design and highly controllable driving of tiny droplets: by laser direct writing of hierarchical patterns with modified wettability and desired geometry on a superhydrophobic film, the patterned film can precisely and directionally drive tiny water droplets and dramatically improve the efficiency of water collection with a factor of similar to 36 compared with the original superhydrophobic film. Such a patterned film might be an ideal platform for water collection from humid air and for planar microfluidics without tunnels
Generic synthesis and versatile applications of molecularly organic-inorganic hybrid mesoporous organosilica nanoparticles with asymmetric Janus topologies and structures
No full textNational Key Research and Development Program of China [2016YFA0203700]; Shanghai Natural Science Foundation [16ZR1440300]; National Natural Science Foundation of China [61275208, 51302293, 51672303]; Shanghai Rising-Star Program [14QA1404100]; Youth Innovation Promotion Association of the Chinese Academy of Sciences [2013169]; Development Fund for Shanghai TalentsPrecise control over the morphology, nanostructure, composition, and particle size of molecularly organic-inorganic hybrid mesoporous organosilica nanoparticles (MONs) still remains a major challenge, which severely restricts their broad applications. In this work, an efficient bridged organic group-determined growth strategy has been proposed for the facile synthesis of highly dispersed and uniform MONs with multifarious Janus morphologies, nanostructures, organic-inorganic hybrid compositions, and particle sizes, which can be easily controlled simply by varying the bridged organic groups and the concentration of bis-silylated organosilica precursors used in the synthesis. In addition, the formation mechanism of Janus MONs determined by the bridged organic group has been discussed. Based on the specific structures, compositions, and asymmetric morphologies, all the synthesized Janus MONs with hollow structures (JHMONs) demonstrate excellent performances in nanomedicine as desirable drug carriers with high drug-loading efficiencies/capacities, pH-responsive drug releasing, and enhanced therapeutic efficiencies, as attractive contrastenhanced contrast agents for ultrasound imaging, and as excellent bilirubin adsorbents with noticeably high adsorption capacities and high blood compatibilities. The developed versatile synthetic strategy and the obtained JHMONs are extremely important in the development and applications of MONs, particularly in the areas of nanoscience and nanotechnology
Structure and optical properties of Er-doped CaO-Al2O3 (Ga2O3) glasses fabricated by aerodynamic levitation
No full textNational Natural Science Foundation of China [61475047, 11504323]; Science and Technology Department of Zhejiang Province [2015C31045]; Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques, South China University of Technology; State Key Laboratory of Precision Spectroscopy. State Key Laboratory of High Field Laser PhysicsWe fabricated a series of stable Er-doped CaO-Al2O3(Ga2O3) glasses by aerodynamic levitation (ADL) method. Using thermal analysis, we studied the influence of composition on the thermal stability of the glasses. The results unraveled the significance of composition on the stability of glasses. Magic angle spinning nuclear magnetic resonance (MAS-NMR) and Raman spectra were used to analyze the glass microstructure. The optical and spectroscopic properties were examined by UV-Vis absorption, steady-state fluorescence spectroscopy, transient state fluorescence spectroscopy, and luminescence quantum yield measurements. The results unraveled a clear concentration-dependent up-conversion and NIR emissions of Er3+, with obvious spectral broadening and redshift. The related mechanisms of decrease in fluorescent lifetime (from about 9ms to 2ms) and quantum yield (from about 75% to 5%) are discussed
Sodium guide star laser pulsed at Larmor frequency
No full textNational Natural Science Foundation of China (NSFC) [61378026, 61575210]589 nm lasers pulsed at Larmor frequency, several hundreds of kilohertz, can increase the brightness of a sodium guide star and are required in remote magnetometry with mesospheric sodium. By amplification of a continuous-wave single-frequency 1178 nm laser in a pulse-pumped Raman fiber amplifier and frequency doubling in an external cavity, high-power pulsed 589 nm laser at Larmor frequency is obtained for the first time, to the best of our knowledge. The pulse format is mainly determined by the 1120 nm Raman pump laser, whose pulse repetition rate and duty cycle are adjustable. Active pulse shaping is applied to minimize the relaxation spike at the leading edge of the pulses. A reduction in pulse width and conversion efficiency from 1120 to 1178 nm is observed in the backwardly pumped Raman fiber amplifier due to the pump pulse transition effect. A 589 nm laser pulsed at a 350 kHz repetition rate and 20% duty cycle with average power up to 17 W is demonstrated as an operation example intended for a geomagnetic field of 0.5 G