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Electro-optical properties of high birefringence liquid crystal compounds with isothiocyanate and naphthyl group

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Chinese physics B 2017年第9期26卷 242-247页

作者：彭增辉王启东王少鑫姚丽双刘永刚胡立发曹召良穆全全杨程亮宣丽 State Key Laboratory of Applied optics Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

Liquid crystal（LC） compound with isothiocyanate and naphthyl group is an attractive high birefringence LC material,and can be used in optical devices. In this paper, the electro-optical properties of a series of this type of LC compounds were investigated. The melting points and enthalpy values of these LC compounds were higher than those of corresponding compounds with the phenyl group. These compounds exhibited high birefringence with a maximum value of 0.66. Fluorine substitution in the molecular almost does not affect the birefringence value. When these LC compounds with the naphthyl group were dissolved in a commercial LC mixture, the electro-optical properties depending on temperature were investigated. In the low-temperature region, LC mixtures with the naphthyl-group LC compounds exhibited higher viscosity than pure commercial LCs. In the high-temperature region, viscosity values very closely approached each other. When response performance was investigated, figure-of-merit（FoM） values were measured. The Fo M values of LC mixtures containing LC compounds with naphthyl group were lower than those of reference benzene LCs in the low-temperature region. However, in the high-temperature region, the results were reversed. These isothiocyanate LC compounds with naphthyl group can be applied in special fast-response LC device, particularly the ones used under high-temperature conditions.

关键词： naphthalene isothiocyanate liquid crystals high birefringence electro-optical property

The effects of ultrasound frequency and power on the activation energy in Si-KOH reaction system

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Chinese Chemical Letters 2014年第4期25卷 617-620页

作者： Qing-Bin Jiao Bayanheshig Xin Tan Ji-Wei Zhu Jian-Xiang Gao changchun institute of optics Fine Mechanics and PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences changchun institute of optics Fine Mechanics and PhysicsChinese Academy of Sciences

The activation energy is the minimum amount of energy required to initiate a reaction. It is one of the important indexes for appraising a reaction. The chemical reaction rate is closely related to the value of activation energy, and reducing activation energy is propitious to promoting a chemical reaction. In the present paper, the relationship between the activation energy in Si-KOH reaction system and the ultrasound frequency and power has been discussed for the first time. The range of ultrasound frequency and power is 40-100kHz （interval by 20kHz） and 10-50W （interval by 10W）, respectively. The experimental clata indicate that the activation energy decreases with the increasing ultrasound power. Comparing with the activation energy without ultrasound irradiation, the results in our paper indicate that ultrasound irradiation could reduce the activation energy in Si-KOH reaction system and increase the reaction rate.

关键词： Si-KOH Etching rate Ultrasonic irradiation Activation energy

Composite structure Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG ceramics with high color spatial uniformity for white laser lighting

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Journal of Advanced Ceramics 2024年第2期13卷 189-197页

作者： Pengfei Sang Le Zhang Jian Kang Mingzhou Li Shiwei Chen Peng Yang Bingheng Sun Yang Li Wieslaw Strek Hao Chen Jiangsu Key Laboratory of Advanced Laser Materials and Devices School of Physics and Electronics EngineeringJiangsu Normal UniversityXuzhou 221116China Jiangsu Xiyi Advanced Materials Research institute of Industrial Technology Xuzhou 221400China Xuzhou EAGLED Technology Co. Ltd.Xuzhou 221116China Xuzhou Kangna Advanced Materials Technology Co. Ltd.Xuzhou 221116China Xuzhou Fuchang Electronic Technology Co. Ltd.Xuzhou 221116China Shanghai institute of optics.fine mechanics Chinese Academy of SciencesShanghai 201800China School of Material Science and Engineering Shanghai Institute of TechnologyShanghai 201418China State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China institute of Low Temperature and Structure Research Polish Academy of SciencesWroclaw 50-422Poland

Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting *** based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal *** this study,a novel composite structure ceramic was designed,including Al_(2)O_(3)-YAG:Ce/YAG layered ceramic with a size of 1 mm×1 mm for lighting,and Al_(2)O_(3) ceramic(φ=16.0 mm)was used as the wrapping material due to its outstanding thermal *** prepared ceramics exhibited excellent thermal performance and no yellow ring *** this design,we achieved the match of the intensity distribution of the blue and yellow lights,resulting in a high angular color uniformity of 0.9 with a view angle of±80°.All ceramics showed no luminous saturation phenomenon,even the laser power density was increased up to 47.51 W/mm^(2).A high-brightness white-light source with a luminous flux of 618 lm,a luminous efficiency of 126 lm/W,a CCT of 6615 K,and a CRI of 69.9 was obtained in the transmissive *** particular,the surface temperature of the ceramic was as low as 74.1℃ under a high laser radiation(47.51 W/mm^(2)).These results indicate that Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.

关键词： Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG angular color uniformity high thermal stability high-power laser lighting

Soliton microcomb generation by cavity polygon modes

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Opto-Electronic Advances 2024年第8期7卷 6-14页

作者： Botao Fu Renhong Gao Ni Yao Haisu Zhang Chuntao Li Jintian Lin Min Wang Lingling Qiao Ya Cheng State Key Laboratory of High Field Laser physics and CAS Center for Excellence in Ultra-Intense Laser Science Shanghai Institute of Optics and Fine Mechanics(SIOM)Chinese Academy of Sciences(CAS)Shanghai 201800China Research Center for Frontier Fundamental Studies Zhejiang LabHangzhou 311100China Engineering Research Center for Nanophotonics&Advanced Instrument Ministry of EducationSchool of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China School of Physical Science and Technology ShanghaiTech UniversityShanghai 200031China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Shanghai Research Center for Quantum Sciences Shanghai 201315China Hefei National Laboratory Hefei 230088China

Soliton microcombs,which require the hosting cavity to operate in an anomalous dispersion regime,are essential to inte-grate photonic *** the past,soliton microcombs were generated on cavity whispering gallery modes(WGMs),and the anomalous dispersion requirement of the cavity made by normal dispersion material was achieved through struc-tural dispersion *** inevitably degrades the cavity optical quality factor(Q)and increases pump threshold power for soliton comb *** overcome the challenges,here,we report a soliton microcomb excited by cavity polygon *** modes display anomalous dispersion at near-infrared while optical Q factors exceeding 4×106 are ***,a soliton comb spanning from 1450 nm to 1620 nm with a record low pump power of 11 mW is demonstrated,a three-fold improvement compared to the state of the art on the same material platform.

关键词： thin-film lithium niobate nonlinear optics microresonators

Study on UV Excitation Properties of Eu 3+ at S6 Site in Bulk and Nanocrystalline Cubic Y2O3

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Journal of Rare Earths 2004年第1期22卷 45-48页

作者：张家骅,贾明理,吕少哲,骆永石,任新光,王笑军 Key Laboratory of Excited State Processes Key Laboratory of Excited State Processes Key Laboratory of Excited State Processes Key Laboratory of Excited State Processes Key Laboratory of Excited State Processes Key Laboratory of Excited State Processes changchun institute of optics fine mechanics and physics Chinese Academy of Sciences changchun 130033 China changchun institute of optics fine mechanics and physics Chinese Academy of Sciences changchun 130033 China changchun institute of optics fine mechanics and physics Chinese Academy of Sciences changchun 130033 China changchun institute of optics fine mechanics and physics Chinese Academy of Sciences changchun 130033 China changchun institute of optics fine mechanics and physics Chinese Academy of Sciences changchun 130033 China changchun institute of optics fine mechanics and physics Chinese Academy of Sciences changchun 130033 China Department of physics Georgia Southern University Statesboro GA 30460 USA

Increases of emission intensities for Eu 3+ at the S 6 site relative to that at the C 2 site were observed as UV excitation wavelength decreases from 300 nm to 200 nm in both bulk and nanocrystalline cubic Y 2O 3:Eu 3+. Decomposition of excitation spectra shows that the charge transfer band of Eu 3+ at the S 6 site lies in the high-energy side of that at the C 2 site, resulting in that the energy transfer from the host prefers to the S 6 site. Detailed emission and excitation spectral characteristics were analyzed and discussed. In addition, spectral red-shift were found in both charge transfer bands in nanocrystalline Y 2O 3:Eu 3+ compared to the bulk material. The number ratio of S 6 sites to C 2 sites is also smaller in nanocrystalline Y 2O 3:Eu 3+ than that in the bulk one.

关键词： charge transfer band UV excitation nano-phosphor rare earths

Extended state observer-based control with an adjustable parameter for a large ground-based telescope

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Research in Astronomy and Astrophysics 2021年第12期21卷 509-518页

作者： Xiao-Xia Yang Yong-Ting Deng Bin Zhang Jian-Li Wang changchun institute of optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

The high-precision requirements will always be constrained due to the complicated operating conditions of the ground-based telescope. Owing to various internal and external disturbances, it is necessary to study a control method, which should have a good ability on disturbance rejection and a good adaptability on system parameter variation. The traditional proportional-integral(PI) controller has the advantage of simple and easy adjustment, but it cannot deal with the disturbances well in different situations. This paper proposes a simplified active disturbance rejection control law, whose debugging is as simple as the PI controller, and with better disturbance rejection ability and parameter adaptability. It adopts a simplified second-order extended state observer(ESO) with an adjustable parameter to accommodate the significant variation of the inertia during the different design stages of the telescope. The gain parameter of the ESO can be adjusted online with a recursive least square estimating method once the system parameter has changed significantly. Thus, the ESO can estimate the total disturbances timely and the controller will compensate them accordingly. With the adjustable parameter of the ESO, the controller can always achieve better performance in different applications of the telescope. The simulation and experimental verification of the control law was conducted on a 1.2-meter ground based telescope. The results verify the necessity of adjusting the parameter of the ESO, and demonstrate better disturbance rejection ability in a large range of speed variations during the design stages of the telescope.

关键词： extended state observer large ground based telescope recursive least square disturbance rejection

Light people:Nobel Laureate *** Betzig

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Light(Science & Applications) 2023年第9期12卷 1718-1726页

作者： Hui Wang Cun Yu changchun institute of optics Fine Mechanics and PhysicsChinese Academy of Sciences130033ChangchunChina

Super-resolution microscopy illuminated the hazy molecular world like a beacon,bringing significant changes to the fields of biology,optics.and *** Betzig,who shared the 2014 Nobel Prize of Chemistry with Stefan Hell and William Moerner,is one of the inventors of this fantastic scientific *** originally on near field optics.*** made a series of stunning achievements at Bell Labs before turning *** he quit,seemingly at the top of his game,to become a hands-on dad and joined the machinery ***,he missed science so much that he made a comeback and wowed everyone instantly with his work.

关键词： optics turning instant

Optimization of linear cavity design of Yb-doped double-clad fiber laser

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Chinese optics.Letters 2004年第3期2卷 148-150页

作者：赵岭张春林李丽娜王力军 changchun institute of optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun 130022

The output characteristics of a linear cavity Yb-doped double-clad fiber (DCF) laser, including the effects of fiber length, fiber loss, and output mirror reflectivity on laser output power and threshold pump power have been studied theoretically and experimentally. In this paper, the linear cavity of double-clad fiber laser (DCFL) was composed of a pair of fiber Bragg gratings, while the facet of fiber was anti-reflection (AR) coated at 1070nm to erase the Fresnel reflection. Analysis showed that the laser output increases as the reflectivity of the fiber Bragg grating used as the output mirror decreases. At last, under the pump power of 14.4 W, single-mode laser output at 1070 am was up to 10.8 W, with slope efficiency of 75 %.

关键词： Fiber Bragg gratings Pumping (laser)

Multi-reference configuration-interaction calculations on multiply charged ions of carbon monosulfide

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Chinese physics B 2013年第2期22卷 159-165页

作者：闫冰张玉娟 institute of Atomic and Molecular physics Jilin University changchun institute of optics Fine Mechanics and PhysicsChinese Academy of Sciences

The potential energy curves for neutrals and multiply charged ions of carbon monosulfide are computed with highly correlated multi-reference configuration interaction *** correlations of inner-shell electrons with the scalar relativistic effects are included in the present *** spectroscopic constants,dissociation energies,ionization energies for ground and low-lying excited states together with corresponding electronic configurations of ions are obtained,and a good agreement between the present work and existing experiments is *** theoretical evidence is found for the adiabatically stable CSq＋（q〉2） ions according to the present ab initio *** calculated values for 1st-6th ionization energies are 11.25,32.66,64.82,106.25,159.75,and 224.64 eV,*** kinetic energy release data of fragments are provided by the present work for further experimental comparisons.

关键词： potential energy curve spectroscopic constants multi-reference configuration interaction kinetic energy release