2016
2016
-
Record 253 of
Title:Hydrothermal synthesis of MoS2 nanosheets films: Microstructure and formation mechanism research
Author(s):Miao, Hui(1,2); Hu, Xiaoyun(1,2); Sun, Qian(1); Hao, Yuanyuan(1); Wu, Hao(1); Zhang, Dekai(1,2); Bai, Jintao(1,2); Liu, Enzhou(3); Fan, Jun(3); Hou, Xun(1,2,4)Source: Materials Letters Volume: 166 Issue: DOI: 10.1016/j.matlet.2015.12.010 Published: March 1, 2016Abstract:MoS2 nanosheets films were successfully prepared by Ti foil assisted hydrothermal synthesis method (labeled as Ti-MoS2 nanosheets films). The downside and upside of the films showed different novel morphologies with nanosheets arranged regularly and flowerlike microspheres, respectively. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). X-ray diffraction patterns showed that the peaks along (002) planes made a wide shift from 14.2° to 9.4° compared to its standard position located at 14.2° at the beginning of the hydrothermal process, then gradually returned back to its normal position with the hydrothermal treatment time going on. However, time was not the only element to influence the position of the main diffraction peaks, a relatively low hydrothermal treatment temperature could also lead to the diffraction peaks' shift. In addition, TEM images indicated that the nanosheets film with hydrothermal treatment time for 24 h had a good single-crystal structure. Otherwise, the formation mechanism was carefully discussed and a possible formation mechanism was proposed. ? 2015 Elsevier B.V.Accession Number: 20155201710584 -
Record 254 of
Title:Ultrafast laser photoinscription of large-mode-area waveguiding structures in bulk dielectrics
Author(s):Stoian, R.(1); D'Amico, C.(1); Bhuyan, M.K.(1); Cheng, G.(1,2)Source: Optics and Laser Technology Volume: 80 Issue: DOI: 10.1016/j.optlastec.2015.11.025 Published: June 2016Abstract:Ultrafast laser photoinscription and laser-based refractive index engineering develop towards a unique way for three-dimensional optical design inside bulk materials for the conception of embedded photonic applications. The specific optical functions for the light guiding elements, notably their single mode characteristics and the accessible spectral domains, depend on the achieved refractive index contrast in the material transparency window and on the characteristic dimensions of the optical modification. We give here an overview of several laser processing options, developed to increase the effective index area and contrast using pulse engineering methods in space and time, and optical design involving focal shaping, tubular concepts, evanescently coupled waveguide arrays, or structured waveguides. ? 2015 Elsevier Ltd. Allrightsreserved.Accession Number: 20160401835538 -
Record 255 of
Title:Broadband antireflective double-layer mesoporous silica coating with strong abrasion-resistance for solar cell glass
Author(s):Wang, Jing(1,4); Yang, Chunming(3); Liu, Yi(3); Zhang, Ce(1,4); Zhang, Cong(1,4); Wang, Mengchao(1,4); Zhang, Jing(1,4); Cui, Xinmin(1,4); Ding, Ruimin(1); Xu, Yao(2)Source: RSC Advances Volume: 6 Issue: 30 DOI: 10.1039/c6ra02281b Published: 2016Abstract:To enhance the efficiency of solar cells, a broadband double-layer antireflective (AR) coating with excellent transmittance and abrasion-resistance, was successfully fabricated using two layer mesoporous silica coatings. Both layers were prepared via a solvent evaporation self-assembly method in which the top- and bottom-layer mesoporous silica coatings used Pluronic F127 and cetyltrimethylammonium bromide (CTAB) as templates, respectively. The grazing incidence small angle X-ray scattering (GISAXS) and the transmission electron microscope (TEM) results indicated that the mesopores in the double-layer AR coating belonged to a Fmmm orthorhombic symmetry structure of the SBA-16 in the top layer and a P6/mmc 3D-hexagonal structure of the MCM-41 in the bottom layer. The solar-weighted average transmittance (TPV) of the broadband AR coating is approximately 99.10% on quartz, 98.62% on borosilicate glass, and 98.55% on K9 glass in the solar spectrum range of 300-2400 nm. By introducing broadband AR coating, the overall power conversion efficiency (η) of the solar cell showed an increase of 1.23% for quartz, 1.31% for borosilicate glass, and 1.37% for K9 glass. Meanwhile, the double-layer AR coating had excellent mechanical stability; the TPV value of coating after abrasion by CS-10F wearaser only decreased 0.16% on quartz, 0.29% on borosilicate glass and K9 glass. The pencil hardness of the double-layer AR coating was found to be 6H. ? The Royal Society of Chemistry 2016.Accession Number: 20161202118965 -
Record 256 of
Title:Sub-micron periodically-poled lithium niobate waveguide for integrated nonlinear optics
Author(s):Chang, Lin(1); Li, Yifei(1); Volet, Nicolas(1); Wang, Leiran(1,2); Peters, Jon(1); Bowers, John E.(1)Source: Optics InfoBase Conference Papers Volume: Issue: DOI: Published: 2016Abstract:We present the first integrable periodically-poled lithium niobate (PPLN) waveguide with a submicron waveguide core that is realized on a silicon nitride thin film lithium niobate platform. Second-harmonic generation based on this device is demonstrated. ? OSA 2016.Accession Number: 20223512643062 -
Record 257 of
Title:Dual-clustering-based hyperspectral band selection by contextual analysis
Author(s):Yuan, Yuan(1); Lin, Jianzhe(1); Wang, Qi(2)Source: IEEE Transactions on Geoscience and Remote Sensing Volume: 54 Issue: 3 DOI: 10.1109/TGRS.2015.2480866 Published: March 1, 2016Abstract:Hyperspectral image (HSI) involves vast quantities of information that can help with the image analysis. However, this information has sometimes been proved to be redundant, considering specific applications such as HSI classification and anomaly detection. To address this problem, hyperspectral band selection is viewed as an effective dimensionality reduction method that can remove the redundant components of HSI. Various HSI band selection methods have been proposed recently, and the clustering-based method is a traditional one. This agglomerative method has been considered simple and straightforward, while the performance is generally inferior to the state of the art. To tackle the inherent drawbacks of the clustering-based band selection method, a new framework concerning on dual clustering is proposed in this paper. The main contribution can be concluded as follows: 1) a novel descriptor that reveals the context of HSI efficiently; 2) a dual clustering method that includes the contextual information in the clustering process; 3) a new strategy that selects the cluster representatives jointly considering the mutual effects of each cluster. Experimental results on three real-world HSIs verify the noticeable accuracy of the proposed method, with regard to the HSI classification application. The main comparison has been conducted among several recent clustering-based band selection methods and constraint-based band selection methods, demonstrating the superiority of the technique that we present. ? 1980-2012 IEEE.Accession Number: 20154201386148 -
Record 258 of
Title:Modeling the encoding structure and spatial resolution of photon counting imagers with Vernier anode readout
Author(s):Yang, Hao(1); Zhao, Baosheng(2); Yan, Qiurong(3); Liu, Yong'an(2)Source: Chinese Optics Letters Volume: 14 Issue: 12 DOI: 10.3788/COL201614.121102 Published: December 10, 2016Abstract:We present the spatial resolution estimation methods for a photon counting system with a Vernier anode. A limiting resolution model is provided according to discussions of surface encoding structure and quantized noise. The limiting resolution of a Vernier anode is revealed to be significantly higher than that of a microchannel plate. The relationship between the actual spatial resolution and equivalent noise charge of a detector is established by noise analysis and photon position reconstruction. The theoretical results are demonstrated to be in good agreement with the experimental results for a 1.2 mm pitch Vernier anode. ? 2016 Chinese Optics Letters.Accession Number: 20170403278940 -
Record 259 of
Title:PH-dependent morphology and its effect on the optical properties of LaF3:Nd nanocrystals
Author(s):Cui, Xiaoxia(1); Guo, Haitao(1); Wei, Wei(1,2); Hou, Chaoqi(1); Gao, Fei(1); Peng, Bo(1,2)Source: Materials Chemistry and Physics Volume: 173 Issue: DOI: 10.1016/j.matchemphys.2016.01.048 Published: April 15, 2016Abstract:Nd3+-doped LaF3 nanocrystals with different morphologies have been produced via solvothermal method at various pH values (1-6). Their morphologies and optical properties were characterized by TEM, fluorescence spectra and decay curves. A possible formation mechanism including burst-nucleation and growth process was proposed. The results reveal that when the pH increases from 1 to 2 to 4-6, the nanocrystals' mean size reduces slightly and the morphologies transform from the hollow sphere to the packed hexagon. The fluorescence lifetime and quantum efficiency achieved maximum for the samples synthesized at pH = 2. These nanocrystals with small size ( ? 2016 Elsevier B.V.Accession Number: 20160501870511 -
Record 260 of
Title:Effective transfer of micron-size graphene to microfibers for photonic applications
Author(s):Wu, Xiaoqin(1); Yu, Shaoliang(1); Yang, Huiran(2); Li, Wenlei(2); Liu, Xueming(2); Tong, Limin(1)Source: Carbon Volume: 96 Issue: DOI: 10.1016/j.carbon.2015.10.069 Published: January 2016Abstract:We demonstrate an effective approach to transferring micron-size CVD graphene layers onto freestanding microfibers. With micro-manipulation, the coating position and length of the graphene films can be precisely controlled. By coating micrometer-scale (e.g., 20 μm) graphene films onto microfibers with diameters down to 1 μm, we can achieve significantly enhanced light-graphene interaction (e.g., a low saturable-absorption threshold of 40 MW/cm2) and simultaneously maintain a high transmission (73% in maximum) as well. In addition, we use these microscale CVD graphene-coated microfibers (GCMs) as saturable absorbers for all-optical modulation at 1550-nm wavelength with a modulation depth of 12% and passively mode-locked fiber lasing with pulse duration down to 970 fs. ? 2015 Elsevier Ltd.Accession Number: 20154801617835 -
Record 261 of
Title:Mode Splitter Without Changing the Mode Order in SOI Waveguide
Author(s):Liao, Jianwen(1,2,3); Zhang, Lingxuan(1,2,3); Liu, Mulong(1,2,3); Wang, Leiran(1,2); Wang, Weiqiang(1,2); Wang, Guoxi(1,2); Ruan, Chi(1); Zhao, Wei(1,2); Zhang, Wenfu(1,2)Source: IEEE Photonics Technology Letters Volume: 28 Issue: 22 DOI: 10.1109/LPT.2016.2606496 Published: November 15, 2016Abstract:We proposed a mode splitter based on directional coupler (DC), which is capable of splitting the TE0 and TE1 modes without changing the mode order. It is found that high coupling efficiency (higher than-1 dB), low mode crosstalk (less than-16 dB), wide bandwidth (~100 nm), and large fabrication tolerance (±10 nm) can be obtained by a 24.4 μm coupling length DC structure, which is composed of a strip and a slot silicon waveguide. This design represents a first step toward mode splitter without changing the mode order, which can find important potential applications, such as optical isolation and mode division multiplexing (MDM), in large-scale photonic integrated circuits (PICs). ? 1989-2012 IEEE.Accession Number: 20173404059660 -
Record 262 of
Title:Directly observing particle manipulations along light trajectories with axial plane optical microscopy
Author(s):Peng, Tong(1); An, Sha(1); Zhou, Xing(1); Han, Guoxia(1); Huang, Zhangxiang(1); Wang, Meirong(2); Yao, Baoli(1); Zhang, Peng(1)Source: Optics InfoBase Conference Papers Volume: Issue: DOI: Published: 2016Abstract:We demonstrate the direct observation of optical particle manipulations along light trajectories with the axial plane optical microscopy (APOM). Optically trapped particles moving along both straight and curved trajectories are successfully monitored by the APOM. ? OSA 2016.Accession Number: 20223512635366 -
Record 263 of
Title:High-energy Q-switched Yb-doped fiber laser based on WS2 film saturable absorber
Author(s):Wang, Junli(1); Li, Sha(1); Wang, Yonggang(3); Zhu, Jiangfeng(1); Wei, Zhiyi(2)Source: Asia Communications and Photonics Conference, ACP Volume: 2016-November Issue: DOI: Published: November 2016Abstract:An all-fiber high-energy Q-switched Yb-doped fiber laser using WS2 film as the saturable absorber (SA) is demonstrated. The highest single pulse energy of 56.50 nJ and the shortest pulse width of 1.0 μs were achieved. Asia Communications and Photonics Conferene (ACP) ? OSA 2016Accession Number: 20203909222289 -
Record 264 of
Title:Transmission volume phase holographic gratings in photo-thermo-refractive glass written with femtosecond laser Bessel beams
Author(s):Zhang, Y.J.(1,2); Zhang, G.D.(2); Chen, C.L.(1); Stoian, R.(3); Cheng, G.H.(2)Source: Optical Materials Express Volume: 6 Issue: 11 DOI: 10.1364/OME.6.003491 Published: 2016Abstract:Transmission volume phase holographic gratings were fabricated in bulk photothermo- refractive glass using zero-order femtosecond laser Bessel beams and subsequent thermal treatment. Microstructures composed of nano-sized crystals were observed in the exposed regions. The concentration of nano-crystals depended on the writing power, but the size of the nano-crystals was found to be quasi power-independent. Low writing power led to sparse nano-crystals, while optimized writing power achieved dense nano-crystals distribution and high refractive index change. Effects of the gratings thickness, writing laser power and thermal treatment on the diffraction efficiency were investigated. A maximum diffraction efficiency of 94.73% was achieved (at 532 nm testing wavelength) with 1 mm grating thickness at period of 5 μm. ? 2016 Optical Society of America.Accession Number: 20164603012278