2019

• Record 457 of
  
  Title:Low-threshold 4/5 octave-spanning mid-infrared frequency comb in a LiNbO3 Microresonator
  
  Author(s):Fan, Weichen(1,2); Wang, Leiran(1,2); Zhang, Wenfu(1,2); Zhao, Wei(1,2); Lu, Zhizhou(1,2); Li, Wei(1,2); Wang, Xinyu(1,2); Zhou, Mengyao(3); Wang, Weiqiang(1); Sun, Qibing(1); Wang, Guoxi(1,2); Cheng, Dong(1,2)
  Source: IEEE Photonics Journal  Volume: 11  Issue: 6  DOI: 10.1109/JPHOT.2019.2949313  Published: December 2019  
  Abstract:Mid-infrared (MIR) optical frequency combs (OFCs) are ideal light sources for precision metrology and can find extensive applications, especially in molecular spectroscopy and gas detection. Here the generation of mode-locked MIR frequency comb in a LiNbO3 microring through optimized slot-waveguide design is proposed. Such microcomb can span over four-fifths of an octave (ranging from ~2810 nm to ~4630 nm) with pump power as low as 50 mW, which can be applied to the 2f-3f self-referencing for fully stabilization and helpful to monolithic integration of the whole system. Further investigations on complex dynamical processes for the microcomb generation suggest that the intracavity soliton drifting caused by the third-order dispersion could be compensated by the self-steepening effect as introducing an additional drift through proper dispersion tailoring. This work could facilitate the low-threshold broadband MIR frequency comb generation technique, as well as provide a way to realize more delicate control of soliton microcombs in both temporal and spectral domain. © 2009-2012 IEEE.
  Accession Number: 20200207992024
• Record 458 of
  
  Title:23.9 W, 985 fs Chirped Pulse Amplification System Based on Yb:YAG Rod Amplifier
  
  Author(s):Wang, Na Na(1,2); Wang, Xiang Lin(1); Zhang, Ting(1); Zhang, Wei(1); Hu, Xiao Hong(1); Yuan, Hao(1); Li, Feng(1); Wang, Yi Shan(1,2); Zhao, Wei(1)
  Source: IEEE Photonics Journal  Volume: 11  Issue: 4  DOI: 10.1109/JPHOT.2019.2926840  Published: August 2019  
  Abstract:A stable and simple Yb:YAG rod amplifier based on chirped pulse amplification in a water cooling system has been demonstrated. The output power of 38 W at a 250 kHz repetition rate with a spectrum width of 4 nm centered at 1030 nm, which support Fourier-transform limited pulse duration of 389 fs has been generated. The compressed power of 23.9 W with pulse duration of 985 fs has been obtained with a chirped volume Bragg grating compressor. The power stability is measured to be 1.414% when the output power is 35 W. The system is worthwhile to popularize for its good performance and inexpensive cost. © 2009-2012 IEEE.
  Accession Number: 20193007233782
• Record 459 of
  
  Title:Comparison Investigation of the Three-dimensional Stiffness of Optical Tweezers with Different Polarization Fields
  
  Author(s):Cao, Zhi-Liang(1,2); Liang, Yan-Sheng(1); Yan, Shao-Hui(1); Zhou, Yuan(1,2); Cai, Ya-Nan(1,2); Lei, Ming(1); Li, Man-Man(1); Yao, Bao-Li(1)
  Source: Guangzi Xuebao/Acta Photonica Sinica  Volume: 48  Issue: 7  DOI: 10.3788/gzxb20194807.0726002  Published: July 1, 2019  
  Abstract:To elucidate the influence of laser polarization state on optical trap stiffness, the three-dimensional stiffness of four kinds of optical traps with different polarization states (azimuthally polarized beam, radially polarized beam, linearly polarized beam, and circularly polarized beam) to trap silica beads with different sizes was investigated. The result show that, when the silica bead's size is equivalent to the laser wavelength, the three-dimensional stiffness of circularly polarized beam and linearly polarized beam are larger than those of radially polarized beam and azimuthally polarized beam. With the increase of the silica bead's size, the three-dimensional stiffness of azimuthally polarized beam and radially polarized beam are larger than those of circularly polarized beam and linearly polarized beam. In addition, the experimental results also show that, when using an oil-immersion objective lens to trap particles, the spherical aberration caused by the mismatch of the refractive index of oil and water will reduce the utilization of the numerical aperture of the objective lens. The work reported in this paper provides a guidance and reference to the force measurement when using trapping beams with different polarization states. © 2019, Science Press. All right reserved.
  Accession Number: 20193407327940
• Record 460 of
  
  Title:Adaptive-window angular spectrum algorithm for near-field ptychography
  
  Author(s):Pan, An(1,2); Zhou, Meiling(1,2); Zhang, Yan(1,2); Min, Junwei(1); Lei, Ming(1); Yao, Baoli(1)
  Source: Optics Communications  Volume: 430  Issue:   DOI: 10.1016/j.optcom.2018.08.035  Published: 1 January 2019  
  Abstract:Near-field ptychography provides advantages over far-field ptychography that large field-of-view (FOV) can be imaged with fewer diffraction images, and with weaker requirements on the detector dynamic range and beam coherence, which has drawn attention recently. However, the propagation distance of traditional angular spectrum (AS) method is limited and the reconstruction of the smallest resolvable object detail is restricted by the sensor's pixel size. To this end, we propose an adaptive-window angular spectrum (AWAS) algorithm to solve both problems by adding the window adaptively associated with the propagation distance and avoid the extra computations via extra scaling factors. Meanwhile, it features validity for the independent sample size and the sample number on the observation plane. This algorithm is strictly deduced from the Rayleigh–Sommerfeld formula and based on the linear convolution, which can be evaluated by fast Fourier transform effectively. The burden of calculations is comparable to traditional AS method. The performance has been achieved both in two-dimensional and three-dimensional near-field ptychography with simulations and experiments. This method will make near-field ptychography more practical and can be used in X-ray or electron-microscopy and other computational imaging techniques. © 2018
  Accession Number: 20183405732339
• Record 461 of
  
  Title:Optical sorting of small chiral particles by tightly focused vector beams
  
  Author(s):Li, Manman(1); Yan, Shaohui(1); Zhang, Yanan(1,2); Liang, Yansheng(1); Zhang, Peng(1); Yao, Baoli(1)
  Source: Physical Review A  Volume: 99  Issue: 3  DOI: 10.1103/PhysRevA.99.033825  Published: March 12, 2019  
  Abstract:The identification and separation of substances by chirality has always been an important problem in biomedical research and industry. Light beams carry optical momentum, and can exert optical force on any object they impinge due to the transfer of momentum. Different chiral objects will experience different optical forces when illuminated by the same light beam. We demonstrate here, based on the dipolar approximation, that a tightly focused vector beam can selectively trap and rotate small chiral particles in the transverse plane via the chirality-tailored optical forces. The radial optical force can transversely trap the chiral particles off axis or push them away depending on the real part of the chirality parameter, while the lateral optical force manifesting as the azimuthal optical force can drive the trapped particles to orbitally rotate with opposite chiral absorption in opposite directions. The study reported here may find applications in discriminating and separating chiral objects with specified chirality. © 2019 American Physical Society.
  Accession Number: 20191106640862
• Record 462 of
  
  Title:Optimization investigation for high-power 1034 nm all-fiber narrowband Yb-doped superfluorescent source
  
  Author(s):Wu, Peng(1,2); Zhao, Baoyin(1); Zhao, Wei(1); Li, Zhe(1); Gao, Wei(1); Ju, Pei(1); Li, Gang(1); Gao, Qi(1); Wang, Yishan(1)
  Source: Optics Communications  Volume: 445  Issue:   DOI: 10.1016/j.optcom.2019.04.033  Published: 15 August 2019  
  Abstract:An optimization for all-fiber narrowband Yb-doped superfluorescent source with a central wavelength shorter than 1040 nm is conducted theoretically and then verified experimentally using steady-state rate equations. Theoretical investigation indicates that with the increase in fiber length, signal power presents one peak value, but the ratio of signal power to output power is decreasing monotonously. Moreover, a filter with high extinction ratio and a gain fiber with high absorption coefficient can have gain suppression on a long wavelength. One all-fiber superfluorescent source is built experimentally on the basis of the theoretically optimized parameters. The source achieves an output power of 214.64 W with a central wavelength of 1034.18 nm and signal–noise ratio of 30 dB. The output power of the source can have further power scaling with considerable available pump power. © 2019 Elsevier B.V.
  Accession Number: 20191606799161
• Record 463 of
  
  Title:Graphene based polarization independent Fano resonance at terahertz for tunable sensing at nanoscale
  
  Author(s):Wang, Kai(1,2); Fan, Wen-Hui(1); Chen, Xu(1); Song, Chao(1,2); Jiang, Xiao-Qiang(1,2)
  Source: Optics Communications  Volume: 439  Issue:   DOI: 10.1016/j.optcom.2019.01.044  Published: 15 May 2019  
  Abstract:A two-dimensional metamaterial structure consisting of polyimide layer covered by a square disk of monolayer graphene and the gold symmetrical split resonance ring is proposed and investigated. Our simulations indicate that the Fano resonance mode in the terahertz range can be generated by this metamaterial structure, and also utilized for nanoscale sensing. The maximum frequency shift is 1671.61 GHz, and the frequency sensitivity is 1.18 THz/RIU for 2-nm-thick analyte. Furthermore, by adjusting the Fermi level of graphene, the resonance frequency can be tuned actively. Different from the Fano resonance excited by asymmetric structure, the proposed structure is polarization-insensitive and can perform well with both TE and TM waves © 2019 Elsevier B.V.
  Accession Number: 20190506452980
• Record 464 of
  
  Title:Real-Time Evolution Dynamics of Double-Pulse Mode-Locking
  
  Author(s):Wang, Guomei(1,2); Chen, Guangwei(1,2); Li, Wenlei(1,2); Zeng, Chao(1,2)
  Source: IEEE Journal of Selected Topics in Quantum Electronics  Volume: 25  Issue: 4  DOI: 10.1109/JSTQE.2019.2922828  Published: July-August 2019  
  Abstract:By means of the emerging dispersive Fourier transform technique, we captured the pulse-resolved spectral evolution dynamics of double-pulse mode-locking in a single-walled carbon nanotube based Er-doped fiber laser from the initial fluctuations, monitoring the evolution process up to 10 s (corresponding to ∼260 million roundtrips) discontinuously. Two distinctly different evolutionary types of double-pulse mode-locking have been investigated in detail: splitting from one pulse and forming simultaneously. Relaxation oscillations, beating dynamics, transient bound state, spectral broadening, and variation of pulse interval have been observed in the evolution processes of the double-pulse mode-locking. Our study will be helpful for the further research of double-pulse mode-locking. © 1995-2012 IEEE.
  Accession Number: 20192607099946
• Record 465 of
  
  Title:SCE: A Manifold Regularized Set-Covering Method for Data Partitioning
  
  Author(s):Li, Xuelong(1,3); Lu, Quanmao(4,5); Dong, Yongsheng(2,6,7); Tao, Dacheng(2,8)
  Source: arXiv  Volume:   Issue:   DOI: null  Published: April 17, 2019  
  Abstract:Cluster analysis plays a very important role in data analysis. In these years, cluster ensemble, as a cluster analysis tool, has drawn much attention for its robustness, stability and accuracy. Many efforts have been done to combine different initial clustering results into a single clustering solution with better performance. However, they neglect the structure information of the raw data in performing the cluster ensemble. In this paper, we propose a Structural Cluster Ensemble (SCE) algorithm for data partitioning formulated as a set-covering problem. In particular, we construct a Laplacian regularized objective function to capture the structure information among clusters. Moreover, considering the importance of the discriminative information underlying in the initial clustering results, we add a discriminative constraint into our proposed objective function. Finally, we verify the performance of the SCE algorithm on both synthetic and real data sets. The experimental results show the effectiveness of our proposed SCE algorithm. Copyright © 2019, The Authors. All rights reserved.
  Accession Number: 20200260389
• Record 466 of
  
  Title:Gap-type dark localized modes in a Bose-Einstein condensate with optical lattices
  
  Author(s):Zeng, Liangwei(1,2); Zeng, Jianhua(1,2)
  Source: Advanced Photonics  Volume: 1  Issue: 4  DOI: 10.1117/1.AP.1.4.046004  Published: July 1, 2019  
  Abstract:Bose-Einstein condensate (BEC) exhibits a variety of fascinating and unexpected macroscopic phenomena, and has attracted sustained attention in recent years - particularly in the field of solitons and associated nonlinear phenomena. Meanwhile, optical lattices have emerged as a versatile toolbox for understanding the properties and controlling the dynamics of BEC, among which the realization of bright gap solitons is an iconic result. However, the dark gap solitons are still experimentally unproven, and their properties in more than one dimension remain unknown. In light of this, we describe, numerically and theoretically, the formation and stability properties of gap-type dark localized modes in the context of ultracold atoms trapped in optical lattices. Two kinds of stable dark localized modes - gap solitons and soliton clusters - are predicted in both the one- and two-dimensional geometries. The vortical counterparts of both modes are also constructed in two dimensions. A unique feature is the existence of a nonlinear Bloch-wave background on which all above gap modes are situated. By employing linear-stability analysis and direct simulations, stability regions of the predicted modes are obtained. Our results offer the possibility of observing dark gap localized structures with cutting-edge techniques in ultracold atoms experiments and beyond, including in optics with photonic crystals and lattices. © The Authors.
  Accession Number: 20215011312971
• Record 467 of
  
  Title:An optical design for dual-band infrared diffractive telescope
  
  Author(s):Wang, Hao(1,2); Kang, Fu-Zeng(1); Zhao, Wei(1); Li, Yi-Chao(1,2)
  Source: Hongwai Yu Haomibo Xuebao/Journal of Infrared and Millimeter Waves  Volume: 38  Issue: 1  DOI: 10.11972/j.issn.1001-9014.2019.01.007  Published: February 1, 2019  
  Abstract:In this paper, the double-layer harmonic diffractive element (HDE) structure is investigated and the optimization procedure is based on the equation of diffraction efficiency of the double-layer diffractive optical element. The diffraction efficiency of the system in the designed middle and far infrared wavebands is larger than 99%, which improves the image contrast and the imagequality significantly. A new dual-band infrared double-layer HDE telescope is designed, which can work in the middle and far infrared wavebands. It is shown that the system approximately attains diffraction limit and is easy to processed. © 2019, Science Press. All right reserved.
  Accession Number: 20192006939407
• Record 468 of
  
  Title:Topological Charge in Situ Measuring of Perfect Optical Vortex
  
  Author(s):Ren, Fei-Fei(1,2); Liang, Yan-Sheng(1); Cai, Ya-Nan(1,2); He, Min-Ru(1); Lei, Ming(1); Yao, Bao-Li(1)
  Source: Guangzi Xuebao/Acta Photonica Sinica  Volume: 48  Issue: 7  DOI: 10.3788/gzxb20194807.0726001  Published: July 1, 2019  
  Abstract:In order to determine the topological charge of a Perfect Optical Vortex (POV), a in-line interferometric measurement method was presented. The basic idea is to use a spatial light modulator to produce a POV and a spherical wave simultaneously. By modulating the divergence angle of the spherical wave, the POV and the spherical wave interfer. The number of interference fringes is used to realize the direct and rapid measurement of topological charge. Simulated and experimental results show that the interference fringes obtained by the method can be used to determine the topological charge of POVs, including the magnitude and symbol. Furthermore, the proposed in situ method is demonstrated to determine the topological charge of the POV array by measuring the interference pattern of a perfect vortex array and a spherical wave. The proposed in situ method is simple and effective. Therefore, it is of a significance for the application of orbital angular momentum control and information coding based on POVs. © 2019, Science Press. All right reserved.
  Accession Number: 20193407327719