Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences
Not a member yet
13355 research outputs found
Sort by
Covalent functionalization of graphene oxide with porphyrin and porphyrin incorporated polymers for optical limiting
No full textPhD Program Foundation of the Ministry of Education of China [20120061110017]; Jilin Science and Technology Development Plan Program of China [20150204001GX]; National Natural Science Foundation of China [61308087, 61522510]; External Cooperation Program of BIC, CAS [181231KYSB20130007]; Strategic Priority Research Program of CAS [XDB160307]; China Scholarship Council (CSC) [201606170189]Porphyrin-graphene composites have attracted increasing attention due to a number of intriguing functions, and their photoelectrical and catalytic performances are expected to be modulated through different approaches. In the present study, a designed polymer based on phenyl sulfone, (p-amino)phenylhydroquinone, and a symmetrical dinaphthylporphyrin were covalently attached to a graphene oxide (GO) sheet. The formation of the nanohybrid was characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Raman, ultraviolet-visible (UV-vis) absorption, steady and transient fluorescence spectroscopy techniques. The nonlinear optical and optical limiting performances of the hybrid were investigated using Z-scan measurements at 532 nm and 1064 nm. For comparison, a porphyrin functionalized GO hybrid was synthesized as a reference. At the same linear transmittance, the polymer functionalized GO exhibited a stronger optical limiting response and a larger nonlinear extinction coefficient than the individual GO, porphyrinated polymer, and porphyrin functionalized GO hybrid analogue, and its intrinsic photophysical mechanism was discussed in detail. More importantly, further improvement of its nonlinear optical properties can be achieved by the chemical reduction of the hybrid. The enhanced nonlinear optical performance originated from the effective combination of nonlinear scattering, reverse saturable absorption, and a possible photo-induced electron/energy transfer mechanism from donor porphyrin moieties in the polymer backbone to acceptor graphene. Our result might provide a new avenue for the development of graphene-porphyrin materials in the field of photocatalysis, nonlinear optics, and optoelectronic devices
Damage threshold influenced by polishing imperfection distribution under 355-nm laser irradiation
No full textA systematic interpretation of laser-induced damage in the nanosecond regime is realized with a defect distribution buried inside the redeposited layer arising from a polishing process. Under the 355-nm laser irradiation, the size dependence of the defect embedded in the fused silica can be illustrated through the thermal conduction model. Considering CeO2 as the major initiator, the size distribution with the power law model is determined from the damage probability statistics. To verify the accuracy of the size distribution, the ion output scaling with depth for the inclusion element is obtained with the secondary ion mass spectrometer. For CeO2 particulates in size of the depth interval with ion output satisfied in the negative exponential form, the corresponding density is consistent with that of the identical size in the calculated size distribution. This coincidence implies an alternative method for the density analysis of photoactive imperfections within optical components at the semi-quantitative level based on the laser damage tests
Fabrication of Ce:(Gd2Y)(Ga3Al2)O-12 scintillator ceramic by oxygen-atmosphere sintering and hot isostatic pressing
No full textNational Nature Science Funds of China [61378069, 61405221]; Youth Innovation Promotion Association of CASA Ce-doped (Gd2Y)(Ga3Al2)O-12 ceramic with good performance was fabricated by sintering in an oxygen atmosphere and hot isostatic pressing. The microstructure as well as the optical and scintillation characteristics of the ceramic was investigated. The ceramic exhibited a high transmittance of 78% in the range of 500-800 nm. The radioluminescence intensity of the ceramic reached up to 30 times that of a bismuth germinate single crystal, and the light yield within 750 ns shaping time was approximately 25800 photons/MeV under (CS)-C-137 gamma-ray irradiation. (C) 2017 Elsevier Ltd. All rights reserved
Grayscale image recording on Ge2Sb2Te5 thin films through laser-induced structural evolution
No full textNational Natural Science Foundation of China [51672292, 61627826, 61137002]Chalcogenide Ge2Sb2Te5 thin films have been widely exploited as binary bit recording materials in optical and non-volatile electronic information storage, where the crystalline and amorphous states are marked as the information bits "0" and "1", respectively. In this work, we demonstrate the use of Ge2Sb2Te5 thin films as multi-level grayscale image recording materials. High-resolution grayscale images are recorded on Ge2Sb2Te5 thin films through taking advantage of laser-induced structural evolution characteristic. Experimental results indicate that the change of laser energy results in the structural evolution of Ge2Sb2Te5 thin films. The structural evolution induces the difference of electronic polarizability and reflectivity, and high-resolution grayscale images are recorded on Ge2Sb2Te5 thin films through direct laser writing method, accordingly
Influence of Tm3+ ions on the amplification of Ho3+: I-5(7) -> I-5(8) transition in fluoride glass modified by Al(PO3)(3) for applications in mid-infrared optics
No full textNational Natural Science Foundation of China [61605192, 51401197]; Guangdong Engineering Technology Research and Development Center of Special Optical Fiber Materials and Devices (South China University of Technology)In this work, we investigate a new type of fluoride glasses modified by Al(PO3)(3) with various Tm3+/Ho3+ doping concentrations. The introduced PO3- plays an effective role in improving the glass-forming ability and thermal stability. Besides, 1.47, 1.8, and 2.0 mu m emissions originating from Tm3+ and Ho3+, respectively, are observed. The spectroscopic properties and energy transfer mechanisms between Tm3+ and Ho3+ are analyzed as well. It is noted that the higher predicted spontaneous transition probability (118.74 s(-1)) along with the larger product of measured decay lifetime and the emission cross section (sigma(emi) x tau) give evidence of intense 2.0 mu m fluorescence
Selective doping of Ni2+ in highly transparent glass-ceramics containing nano-spinels ZnGa2O4 and Zn1+xGa2-2xGexO4 for broadband near-infrared fiber amplifiers
No full textNational Natural Science Foundation of China [61227013, 51302082, 61307104, 61422505, 61405044, 61575050]; National Key Scientific Instrument and Equipment Development Project [2013YQ040815]; Program for New Century Excellent Talents in University [NCET-12-0623]; Open Project Program of the Jiangsu Key Laboratory of Advanced Laser Materials and Devices [KLALMD-2015-07]; Fundamental Research Funds for the Central Universities; 111 project [B13015]Selective doping of Ni2+ in octahedral sites provided by nanocrystals embedded in glass-ceramics (GCs) is crucial to the enhancement of broadband near-infrared (NIR) emission. In this work, a NIR emission with a full- width-at-half-maximum (FWHM) of 288 nm is first reported from ZnGa2O4: Ni2+ nano-spinels embedded GCs with excellent transparency. A comparison is made of the NIR luminescence properties of Ni2+ doped GCs containing ZnGa2O4, germanium-substituted ZnGa2O4 nano-spinels (Zn1+xGa2-2xGexO4), and Zn2GeO4/Li2Ge4O9 composite nanocrystals that are free of Ga3+. The results show that ZnGa2O4: Ni2+ GCs exhibit a significantly enhanced NIR emission. The incorporation of the nucleating agent TiO2 is favored in terms of the increased luminescence intensity and prolonged lifetime. The possible causes for the enhancement effect are identified from the crystal structure/defects viewpoint. The newly developed GCs incorporate good reproducibility to allow for a tolerance of thermal treatment temperature and hence hold great potential of fiberization via the recently proposed "melt-in-tube" method. They can be considered as promising candidates for broadband fiber amplifiers
Solvent-controlled syntheses of mixed-alkali-metal borates exhibiting UV nonlinear optical properties
No full textNational Natural Science Foundation of China [51432006, 50925207, 51172100]; Ministry of Science and Technology of China [2011DFG52970]; Ministry of Education of China for the Changjiang Innovation Research Team [IRT13R24]; Ministry of Education; State Administration of Foreign Experts Affairs for the 111 Project [B13025]; Australian Research CouncilThe mixed-alkali-metal borates NaK(B5O8)(OH)center dot H2O(1), NaK6[(B4O5)(OH)(4)](3)(OH)center dot C2H5OH(2) and Na0.33K1.67(B4O5)(OH)(4)center dot 3H(2)O(3) have been solvothermally synthesized using various polar organic solvents. Compounds 1 and 2 crystallize in the centrosymmetric space groups P (1) over bar and R (3) over barc, respectively. The structure of 1 features a 2D-layered framework constructed by [B5O11](7-) primary building units in the ab plane, extending to a 3D framework linked by K+ and Na+ cations, while the structure of 2 can be described as isolated [B4O9](6-) primary building units connected by H-bonding interactions and K-O and Na-O bonds, forming a 3D supramolecular framework. Compound 3 crystallizes in the acentric space group P (6) over bar 2c, and its UV nonlinear optical properties have been investigated for the first time. Second-harmonic generation(SHG) measurements show that 3 is type-I phase-matching, with a moderate SHG response ca. 0.94 times that of KH2PO4. The cut-off edge of 3 is 242 nm, which suggests that 3 is a potential UV NLO material. Density functional theory calculations have been employed on 3 to rationalize its band structure and electron density as well as the density of states
Studies on the key methods for compressive ghost-image tracking based on background subtraction
No full textEfficient object tracking represents a technology important for many vision applications. It is known that ghost imaging (GI) has a great potential if compared with a standard imaging and solves many problems in case if the common object tracking cannot be carried out. Here we show how the techniques of compressive GI and background subtraction can achieve object tracking. First, object information is captured with the GI. A characteristic measured for an object is obtained by subtracting background in the compressed domain. This characteristic uses compressive sensing to reconstruct the object image. Then the object image is projection-positioned to obtain the corresponding centroid coordinates. At last, the object trajectory is recovered with a polynomial fit, thus providing successful object tracking. Our simulation experiments suggest that the technique can track objects accurately under condition of low sampling ratios. Moreover, it decreases drastically the number of measurements needed for reconstruction and improves the tracking efficiency
Study of effects of Te addition and oxygen contamination on the surface short range order structure of Ge-Bi-Se glass by XPS
No full textShanghai Leading Academic Discipline Project [B502]; Shanghai Key Laboratory Project [08DZ2230500]; National Natural Science Foundation of China [NSFC 51572081, 51572082]; Natural Science Foundation of Shanghai [17ZR1434200]The short range order structure of Bi13Ge20Se67-xTex glasses (x = 0,5,10,15,20 at.%) is explored by using high-resolution X-ray photoelectron spectroscopy. Results show that the incorporated oxygen from surface containment of specimens and Te substitution for Se exert important impacts on the network structure of glasses. Oxygen breaks the Ge-Ge homopolar bonds in the. Ge-Se-Bi glass, leading to a significant reduction of the over-constrained Ge-Ge (Se)(3) ethane-like units. Te addtion promotes the formation of mixed BiSe(Te)(3/2) nanolayers as crystal precursors, thus initiating crystallinzation in competition to a topological self-organization process. The present work will be helpful to deepen the understanding of ChG glasses for applications in fields of optoelectronics and photonics. (C) 2017 Elsevier B.V. All rights reserved
A hybrid Gerchberg Saxton-like algorithm for DOE and CGH calculation
No full textThe Gerchberg-Saxton (GS) algorithm is widely used in various disciplines of modern sciences and technologies where phase retrieval is required. However, this legendary algorithm most likely stagnates after a few iterations. Many efforts have been taken to improve this situation. Here we propose to introduce the strategy of gradient descent and weighting technique to the GS algorithm, and demonstrate it using two examples: design of a diffractive optical element (DOE) to achieve off-axis illumination in lithographic tools, and design of a computer generated hologram (CGH) for holographic display. Both numerical simulation and optical experiments are carried out for demonstration. (C) 2016 Elsevier Ltd. All rights reserved