2019

• Record 385 of
  
  Title:Review on the new technologies to improve the resolution of spatial optical remote sensor
  
  Author(s):Xiang, Meng(1,2); Li, Chuang(1); Zhao, Yiyi(1); Hu, Bin(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 10837  Issue:   DOI: 10.1117/12.2504941  Published: 2019  
  Abstract:Space optical remote sensors play an important role in earth observation, space situation awareness and astronomy exploration. The optical resolution of space remote sensing system is constantly improved. Several new techniques for realizing ultra-high resolution of spatial optical remote sensors are reviewed. The research status and application prospects of these new technologies are discussed, mainly including synthetic aperture optical system, Fourier ptychography and intensity correlation imaging. The critical technical problems of these new technologies in spacebased and ground-based optical remote sensing engineering are summed up. © 2019 SPIE.
  Accession Number: 20190506432452
• Record 386 of
  
  Title:Optically active beams: Non-reciprocal optical activity in free space induced by spin-orbital interaction of light
  
  Author(s):Liu, Sheng(1); Qi, Shuxia(1); Li, Peng(1); Wei, Bingyan(1); Chen, Peng(2); Hu, Wei(2); Zhang, Yi(1); Gan, Xuetao(1); Zhang, Peng(3); Lu, Yanqing(2); Chen, Zhigang(4); Zhao, Jianlin(1)
  Source: arXiv  Volume:   Issue:   DOI: null  Published: August 26, 2019  
  Abstract:Optical activity, the power of a medium to rotate the polarization of a light beam, has contributed significantly to molecular structure assessments in stereochemistry, biomolecular science and crystallography. Thus far, it is commonly believed that optical activity is manifested only in the chiral media which can give rise to circular birefringence of light. Here, we experimentally demonstrate that free space can also support the implementation of nonreciprocal optical activity with Bessel beams by spin-orbital interaction. Specifically, non-diffractive optically active beams are realized, with their optical rotatory power readily controlled by simple optical elements. We show that such free-space optical activity can be exploited to form non-reciprocal optical components such as polarization rotators, isolators, and circulators. Our results may bring about new possibilities of media-independent optical activity to other transverse waves ranging from radio to optical frequencies. Copyright © 2019, The Authors. All rights reserved.
  Accession Number: 20200301650
• Record 387 of
  
  Title:Development of high power annular diode laser array using hard solder
  
  Author(s):Hou, Dong(1); Sun, Lichen(1); Fu, Tuanwei(1); Chen, Li(1); Liang, Xuejie(1); Cai, Lei(1); Yang, Yan(1); Wang, Jingwei(1); Yan, Minna(1); Zah, Chungen(1); Liu, Xingsheng(1,2)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 10899  Issue:   DOI: 10.1117/12.2510023  Published: 2019  
  Abstract:High power QCW diode laser stacks have been widely used in pumping applications for years. Different package structures of diode laser stacks are applied for pumping the cylindric rod cryst, such as modular G-Stack, horizont, vertic and annular arrays. Annular array is preferred in pumping of QCW mode with low duty cycle and short pulse width, due to the advantage of compact structur size, uniform light beam distribution and convenient electric connection. However, the development of annular diode laser array using hard solder is difficult because of the complex bonding process of diode laser on annular heatsink with convention bonding fixture. Furthermore the stress and therm behavior is yet to be well studied on the annular diode laser array. In this work, a sophisticated annular diode laser array was developed using hard solder. Optimized structure and therm design were conducted to achieve uniform light beam distribution and good heat dissipation. Stress release structure of diode laser stack is applied to reduce the risk of chip crack and deviation of spati spectrum. The annular diode laser array consists of 44 bars in a ring, with the peak output power of each bar over 500W. The maximum output power of each bar reaches 673 W. © 2019 Downloading of the abstract is permitted for person use only.
  Accession Number: 20192206988962
• Record 388 of
  
  Title:An analytical model to predict the sizes of modified layer in glass with femtosecond Bessel beam
  
  Author(s):Liao, Kai(1,2,3); Wang, Wenjun(1,2,3); Mei, Xuesong(1,2,3); Cui, Jianlei(1,2,3); Li, Ming(4); Li, Xun(4)
  Source: Optik  Volume: 185  Issue:   DOI: 10.1016/j.ijleo.2019.03.071  Published: May 2019  
  Abstract:Femtosecond Bessel beam is advantageous in high-quality glass cutting because of its resistance to diffraction. However, the sizes of the modified layer in the glass ablated by Bessel beam can be affected by many factors. In this study, an analytical model to predict the sizes(the depth and the maximum diameter) of modified layer in glass with femtosecond Bessel beam based on an axicon through an orthogonal experiment L16(44) was conducted. The coefficient values of four factors are obtained through the Matlab multiple linear regression function based on the experimental data. Simultaneously, the significance of the regression equation was tested by using the F-value test and the verification test. It found that the experimental results are consistent with the theoretical results. The combined processing parameters with the largest aspect ratio are determined through the range analysis and the influence of the various factors on the sizes was obtained. Finally, an application of thin glass cutting by the internal modification and breaking process is demonstrated. The glass is well cut with the chipping on the breaking edge © 2019 Elsevier GmbH
  Accession Number: 20191406722593
• Record 389 of
  
  Title:Aberration correction method based on double-helix point spread function
  
  Author(s):Wang, Zhaojun(1,2); Cai, Yanan(1,2); Liang, Yansheng(1,2); Dan, Dan(1,3); Yao, Baoli(1,3); M., Lei
  Source: Journal of Biomedical Optics  Volume: 24  Issue: 3  DOI: 10.1117/1.JBO.24.3.031005  Published: March 1, 2019  
  Abstract:Point spread function (PSF) engineering has met with lots of interest in various optical imaging techniques, including super-resolution microscopy, microparticle tracking, and extended depth-of-field microscopy. The intensity distributions of the modified PSFs often suffer from deteriorations caused by system aberrations, which greatly degrade the image contrast, resolution, or localization precision. We present an aberration correction method using a spiral-phase-based double-helix PSF as an aberration indicator, which is sensitive and quantitatively correlated to the spherical aberration, coma, and astigmatism. Superior to the routine iteration-based correction methods, the presented approach is iteration-free and the aberration coefficients can be directly calculated with the measured parameters, relieving the computing burden. The validity of the method is verified by both examining the intensity distribution of the conventional Gaussian PSF in three dimensions and observing muntjac skin fibroblast cells. This iteration-free correction method has a potential application in PSF engineering systems equipped with a spatial light modulator. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
  Accession Number: 20183805826511
• Record 390 of
  
  Title:On-chip polarization beam splitter with multimode operation in a SOI waveguide
  
  Author(s):Ge, Zhiqiang(1,2); Li, Xingyi(1); Li, Siqi(1); Liu, Mulong(1); Si, Jinhai(2); Zhang, Lingxuan(1)
  Source: Japanese Journal of Applied Physics  Volume: 58  Issue: 1  DOI: 10.7567/1347-4065/aaef92  Published: January 2019  
  Abstract:The polarization beam splitter (PBS) based on the directional coupler is numerically investigated to operate transverse-electric (TE) and transverse-magnetic (TM) modes including high-order modes. Based on the phase-matching condition, all TM-polarization modes are switched from the bus waveguide to the adjacent waveguide without changing the spatial profile of the electric field and mode order while all TE-polarization modes go along the bus waveguide without significant coupling. The results show a low cross talk characteristic (>20 dB at 1.55 μm) and big fabrication tolerance (δw = ±20 nm). It becomes an essential supplement for polarization splitting with multimode operation in photonics integrated circuits. © 2018 The Japan Society of Applied Physics.
  Accession Number: 20190306379381
• Record 391 of
  
  Title:Gain characteristics of a high nonlinearity graphene silicon-based hybrid waveguide
  
  Author(s):Chen, Hongji(1,3); Liu, Hongjun(1,2); Wang, Zhaolu(1); Huang, Nan(1); Huo, Yiping(3)
  Source: Japanese Journal of Applied Physics  Volume: 58  Issue: 7  DOI: 10.7567/1347-4065/ab2a7c  Published: 2019  
  Abstract:We demonstrate a phase-sensitive amplifier based on a high nonlinearity graphene silicon-based hybrid waveguide. Dispersion characteristics of the phase-sensitive amplifier are adjustable via chemical potential of the graphene, and the zero dispersion point right shifts with the chemical potential increasing. Single-trench waveguide structure makes the TE mode strictly limited to the trench. The effective mode area is 0.25 μm2. An organic material with low two-photon absorption and high Kerr index is filled in the trench to provide a large nonlinear parameter of 3500 W-1 m-1. The proposed amplifier has a gain of 35 dB with a length of 1.25 mm. © 2019 The Japan Society of Applied Physics.
  Accession Number: 20193407331259
• Record 392 of
  
  Title:Suspended graded-index porous core POF for ultra-flat near-zero dispersion terahertz transmission
  
  Author(s):Mei, Sen(1,2); Kong, Depeng(1); Wang, Lili(1); Ma, Tian(3); Zhu, Yuanfeng(4,5); Zhang, Xiaodong(1,2); He, Zhengquan(1); Huang, Xiangsheng(6); Zhang, Yani(1,7)
  Source: Optical Fiber Technology  Volume: 52  Issue:   DOI: 10.1016/j.yofte.2019.101946  Published: November 2019  
  Abstract:A suspended graded-index porous core polymer optical fiber (POF) for low-dispersion terahertz guidance is proposed. This fiber is consisting of a graded-index porous core, five spoke-like dielectric supporting strips and an outer material ring. The finite element method (FEM) with perfectly matched layer boundary conditions is used to simulate the guiding properties. It is found that by creating artificial graded-index in the porous core, an extremely flat group velocity dispersion (GVD) of 0.14 ± 0.07 ps/(THz·cm) is achieved in the range of 0.71–0.95 THz when fiber core diameter is 432 μm and the air porosity is 44%. Meanwhile, the fiber shows low and flat intermodal dispersion of 0.0152 ± 0.0004 ps/(THz·cm) at 0.8–1 THz under the same conditions. Moreover, other optical parameters of the fiber such as confinement loss (CL), effective material loss (EML) and normalized frequency V are also investigated. © 2019 Elsevier Inc.
  Accession Number: 20192507059348
• Record 393 of
  
  Title:Three-dimension al. steady-state thermal. model of a high power diode laser
  
  Author(s):Wu, Di-Hai(1); Zah, Chung-En(2); Liu, Xingsheng(3)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 10899  Issue:   DOI: 10.1117/12.2506494  Published: 2019  
  Abstract:Heat conduction is of great importance in thermal. design for high power diode lasers. In this paper, an anal.ytic, threedimension, steady-state, multilayered, thermal. model for a high power diode laser is derived. The temperature and heat flux distribution are discussed for an epi-down bonded broad-Area diode laser, and it is found that heat spreading within laser chip contributes 6.8% to total. heat dissipation. Further discussion is carried out on heat flow in the submount to show the submount size requirement for which this model can be used. Simulation result based on finite element method (FEM) is employed to confirm the cal.culation accuracy from this anytic model. © 2019 Downloading of the abstract is permitted for person use only.
  Accession Number: 20192206988957
• Record 394 of
  
  Title:A hollow ring-core polymer optical fiber for supra-high bandwidth data communication
  
  Author(s):Yuan, Yuan(1,2); Kong, Depeng(1); Wang, Lili(1)
  Source: Optics Communications  Volume: 441  Issue:   DOI: 10.1016/j.optcom.2019.02.055  Published: 15 June 2019  
  Abstract:Bandwidth of polymer optical fiber (POF) is severely limited in a few gigabits. In order to solve the toughest problem, a new type of POF, named hollow ring-core POF (HRC-POF) is designed and simulated. Compared with the SI-POF and GI-POF, the proposed HRC-POF can be used for supra-high bandwidth data transmission based on OAM-based space division multiplex. Compared with the reported glass-based hollow ring-core fiber, the HRC-POF provides a number of other advantages, such as low processing temperature, simple manufacturing process, and low cost. The simulated results show that a polystyrene-based HRC-POF can support 30 states (including 26 OAM ones) in the vicinity of 670 nm wavelength, which means that the HRC-POF can create a total of 30 channels for data transmission in POF communication. © 2019 Elsevier B.V.
  Accession Number: 20191006599598
• Record 395 of
  
  Title:Research on image denoising algorithm based on improved anisotropic diffusion synthetic aperture radar
  
  Author(s):Xin, Hongqiang(1,2); Feng, Liangjie(1,2)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 11069  Issue:   DOI: 10.1117/12.2524184  Published: 2019  
  Abstract:The presence of speckle noise seriously affects the application of synthetic aperture radar (SAR) images in image fusion, so it is especially important to suppress speckle noise. According to the formation mechanism of speckle noise, this paper proposes a SAR image speckle noise removal algorithm based on improved anisotropic diffusion. The algorithm improves the diffusion coefficient c(x) based on the P-M equation diffusion filter algorithm, and adds the iterative termination condition, and obtains the filtering algorithm suitable for SAR images. This method can not only solve the problem that there are many isolated noise points in the traditional P-M model filtering, but also has a good effect on image edge preservation. The simulation results show that the improved P-M model can eliminate noise well and maintain the edge information of the image well. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
  Accession Number: 20192106949150
• Record 396 of
  
  Title:A chirped fiber Bragg grating with triple functions for stable wavelength-tunable Yb-doped fiber laser
  
  Author(s):Yang, Huiran(1); Li, Wenlei(2); Chen, Guangwei(2)
  Source: Infrared Physics and Technology  Volume: 102  Issue:   DOI: 10.1016/j.infrared.2019.103008  Published: November 2019  
  Abstract:Chirped fiber Bragg gratings (CFBGs) have been extensively employed as dispersion compensation element in mode-locked fiber lasers. However, multiple functions of CFBG in fiber lasers have not been studied adequately. Here, triple functions of CFBG, dispersion compensation, distributed reflection performance, and stabilizing mode-locked operation, are experimentally investigated. Firstly, the generation of dissipative solitons (DSs) in an all-normal-dispersion Yb-doped fiber laser is reported, while the mode-locked operation is proved to be insufficiently stable. In order to improve performance of the laser, a conventional solitons (CSs) fiber laser is obtained by inserting a CFBG with large anomalous dispersion into the laser cavity. Besides, the distributed reflection performance of CFBG is researched and a wavelength-tunable fiber laser with tuning range of center wavelength from 1033.5 to 1035.5 nm is achieved. It is no doubt that our work opens up venues to create wavelength tunable Yb-doped fiber laser systems with extremely high stability. © 2019 Elsevier B.V.
  Accession Number: 20193207298660