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birefringence Grating and Surface Grating in Azobenzene Polymer Liquid Crystal Films Investigated by Near—Field Optical method

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Chinese Physics Letters 2003年第7期20卷 1043-1046页

作者：章江英明海王沛孙晓红鲁拥华吴云霞谢建平张其锦刘剑谢爱芳张泽渤顾本源 DepartmentofPhysics universityofScienceandTechnologyofchinaHefei230026 StructureResearchLaboratory universityofScienceandTechnologyofchinaChineseAcademyofSciencesHefei230026 DepartmentofPolymerScienceandEngineering universityofScienceandTechnologyofChinaHefei230026 LaboratoryofOpticalPhysics InstituteofPhysicsChineseAcademyofScinecesBeijing100080

The birefringence grating and the surface grating in azobenzene polymer liquid-crystal (Azo-PLC) films are studied by a near-field scanning optical microscope. With laser irradiation, the refractive index change caused by birefringence and the sinusoidal surface profile are observed at the near-field transmittance image and the surface topography of the grating. The grating period and the peak-to-peak value of the sinusoidal surface profile are 0.8 μm and 40 nm, respectively. The maximum diffractive efficiency of the grating is 2%. The dynamic process of the grating formation is probed and analysed. The mass diffusion responsible for the formation of the surface grating due to the temperature rise is analysed.

关键词： azobenzene near-field birefringence Laser radiation Liquid crystal polymers

From borophosphate to fluoroborophosphate:a rational design of fluorine-induced birefringence enhancement

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Science China Chemistry 2021年第9期64卷 1498-1503页

作者： Wenyao Zhang Zhizhong Zhang Wenqi Jin Ruonan Zhang Meng Cheng Zhihua Yang Shilie Pan CAS Key Laboratory of Functional Materials and Devices for Special Environments Xinjiang Technical Institute of Physics&ChemistryCASXinjiang Key Laboratory of Electronic Information Materials and DevicesUrumqi830011China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing100049China

The introduction of oxofluoride anion into anionic group assists to tune optical properties owing to the change of coordination,electronegativity,and according anionic ***,we proposed a rational design of new compounds by fluorine-driven structure and optical property evolution.A new borophosphate Ba_(2)BP_(3)O_(11)with the monoclinic space group P2_(1/c) has been synthesized in the sealed ***_(2)BP_(3)O_(11)exhibits a rare P-O-P bridge formation,which is the first example in alkaline-earth metal *** further substituting[BO_(4)]^(3-)with[BO_(3)F]^(4-),the first alkaline-earth metal/lead fluoroborophosphates M_(2)BP_(2)O_(8)F(M=Ba and Pb)with the same space group were *** the scissors effect of fluorine,in M_(2)BP_(2)O_(8)F(M=Ba and Pb),a BO_(3)F tetrahedron corner-sharing with three PO_(4)tetrahedra forms 1D chains along the b-axial direction,which are filled by MO_(n)(M=Ba/Pb,n=5,6,8)distorted *** first principles calculation shows that the borophosphate Ba_(2)BP_(3)O_(11)has a birefringence about 0.013@1,064 nm,while the fluoroborophosphates M_(2)BP_(2)O_(8)F(M=Ba and Pb)have the values of 0.035 and 0.043@1,064 nm,*** an apparent enhancement in birefringence is derived from synergies of the oxyfluoride and *** introduction of fluorine-containing heteroanionic groups provides a feasible strategy to design novel promising optical materials.

关键词： borophosphate fluoroborophosphates P-O-P bridges formation birefringence

Effect of thermally induced birefringence on high power picosecond azimuthal polarization Nd:YAG laser system

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Chinese Physics B 2019年第2期28卷 234-240页

作者： Hongpan Peng Ce Yang Shang Lu Ning Ma Meng Chen Laser Engineering Research Institute Beijing University of Technology

Pulse-burst 1064-nm picosecond azimuthal polarization beam amplification up to an average power of 16.32 W using side-pumped Nd: YAG amplifiers has been demonstrated. The maximum envelop energy as much as 16.32 mJ, corresponding to a power amplification factor of 299.5%. A simple criterion was defined to help estimate the amount of depolarization in Nd:YAG amplifier stages. The degree of depolarization of the beam was 7.1% and the beam quality was measured to be M2= 3.69. The reason for the azimuthal polarization depolarization and beam quality degradation were explained theoretically and experimentally during the amplification process.

关键词： azimuthal polarization thermally induced birefringence Nd:YAG amplifiers picosecond laser

Review on birefringence in borates based on birefringence-active functional groups and arrangements

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Science China Chemistry 2024年第7期67卷 2155-2170页

作者： Qianzhen Zhang Ran An Zhihua Yang Xifa Long Shilie Pan Yun Yang Research Center for Crystal Materials State Key Laboratory of Functional Materials and Devices for Special Environmental ConditionsXinjiang Key Laboratory of Functional Crystal MaterialsThe Xinjiang Technical Institute of Physics&ChemistryChinese Academy of SciencesUrumqi 830011China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

As a fundamental parameter of the optical crystals,birefringence plays a vital role in many optical applications,such as phase modulation,light splitting,and polarization,especially the phase matching process of the nonlinear optical *** big birefringence not only benefits to the miniaturization of related devices,but also broadens the phase-matching wavelength range of nonlinear optical *** design and synthesis of crystals with large birefringence becomes a hot research topic due to its more and more important applications in the optical modulation and laser technology ***,crystals with birefringence greater than 0.05 in the borate system are reviewed and classified according to different birefringent active groups,and the relationship between structure and properties is thoroughly *** is hoped that this review will provide a clear understanding of what kinds of building units and arrangements would have more opportunity to get adequate birefringence in borate systems and provide the statistical references to encourage the emergence of better crystal materials with large birefringence.

关键词： birefringence borate optical functional crystal structural anisotropy arrangement of functional units

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Coupled thermal-optic effects and electrical modulation mechanism of birefringence crystal with Gaussian laser incidence

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Chinese Physics B 2015年第9期24卷 223-234页

作者：周吉贺志宏马宇董士奎 School of Energy Science and Engineering Harbin Institute of Technology

We study the Gaussian laser transmission in lithium niobate crystal（LiNbO3） by using the finite element method to solve the electromagnetic field＇s frequency domain equation and energy equation. The heat generated is identified by calculating the transmission loss of the electromagnetic wave in the birefringence crystal, and the calculated value of the heat generated is substituted into the energy equation. The electromagnetic wave＇s energy losses induced by its multiple refractions and reflections along with the resulting physical property changes of the lithium niobate crystal are *** of ambient temperature and heat transfer coefficient on refraction and walk-off angles of O-ray and E-ray in the cases of different incident powers and crystal thicknesses are analyzed. The E-ray electrical modulation instances, in which the polarized light waveform is adjusted to the rated condition via an applied electrical field in the cases of different ambient temperatures and heat transfer coefficients, are provided to conclude that there is a correlation between ambient temperature and applied electrical field intensity and a correlation between surface heat transfer coefficient and applied electrical field intensity. The applicable electrical modulation ranges without crystal breakdown are proposed. The study shows that the electrical field-adjustable heat transfer coefficient range becomes narrow as the incident power decreases and wide as the crystal thickness increases. In addition, it is pointed out that controlling the ambient temperature is easier than controlling the heat transfer coefficient. The results of the present study can be used as a quantitative theoretical basis for removing the adverse effects induced by thermal deposition due to linear laser absorption in the crystal, such as depolarization or wave front distortion, and indicate the feasibility of adjusting the refractive index in the window area by changing the heat transfer boundary con

关键词： birefringence electro-optic modulators thermo-optic effects

Temperature dependence of birefringence in olarization-maintaining photonic crystal fibres

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Chinese Physics B 2012年第6期21卷 554-559页

作者：赵红陈檬李港 Beijing University of Technology Institute of Laser Engineering

In this paper,the temperature dependence of birefringence in polarization maintaining photonic crystal fibres（PMPCFs） is investigated theoretically and *** the structural parameters of the PM-PCF samples in the experiment,two effects leading to the birefringence variation under different temperatures are analysed,which are the thermal expansion of silica material and the refractive index variation due to the temperature *** actual birefringence variation of the PM-PCF is the combination of the two effects,which is in the order of 10-9 K-1 for both fibre *** results also show that the influence of refractive index variation is the dominant contribution,which determines the tendency of the fibre birefringence variation with varying ***,the birefringence beat lengths of the two fibre samples are measured under the temperature,which varies from -40℃ to 80℃.A traditional PANDA-type polarization maintaining fibre（PMF） is also measured in the same way for *** experimental results indicate that the birefringence variation of the PM-PCF due to temperature variation is far smaller than that of the traditional PMF,which agrees with the theoretical *** ultra-low temperature dependence of the birefringence in the PM-PCF has great potential applications in temperature-insensitive fibre interferometers,fibre sensors,and fibre gyroscopes.

关键词： birefringence polarization-maintaining fibre photonic crystal fibre temperature depen-dence

Mueller matrix analysis for all optical fiber co-existence of birefringence-polarization dependent gain-mode coupling at a single wavelength

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Chinese Physics B 2011年第11期20卷 13-18页

作者：尚超吴重庆李政勇杨双收高凯强余贶琭冯震 Key Laboratory of Education Ministry on Luminescence and Optical Information Technology Institute of Optical InformationBeijing Jiaotong University

birefringence （polarization-related phase-shift）, polarization dependent gain （PDG） and mode coupling are three factors that may synchronously influence the transmission of single-wavelength polarized light in optical fibers. This paper obtains a new Mueller matrix analysis, which can be used under conditions that all these three factors are existing and changing. According to our transmission model, the state of polarization （SOP） changes along an optical mierostructure fiber with co-existence of birefringence-PDG-mode coupling were simulated. The simulated results, which show the phenomena of SOP constringency, are in good agreement with previous theoretical analyses.

关键词： Mueller matrix birefringence polarization dependent gain mode coupling

Wavelength-selective characteristics of high birefringence photonic crystal fiber with Au nanowires selectively filled in the cladding air holes

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Chinese Physics B 2012年第9期21卷 359-365页

作者：杜颖李曙光刘硕 Key Laboratory of Metastable Materials Science and Technology College of ScienceYanshan University

Filter characteristics of a designed gold-filled high birefringence photonic crystal fiber are investigated based on the finite element method. The wavelength filter resonances in the high birefringence photonic crystal fiber occur at different points for different polarized directions, and the resonance strength in the x-polarized case is much weaker than that in the y-polarized case. The much more obvious splitting filter characteristics and different resonance strength imply the study and application values in splitting and single polarization fiber devices. The simulation results show that increasing the number of the gold wires only enhances the resonance strength when there is no surface plasmon supermode formed. With the diameters of the gold wires increasing, the response wavelength moves to a longer wavelength, and the strength becomes stronger. When the diameter is increased to 1.4 μm, the response wavelength in the x-polarized case can be tuned to 1.318 gin, which is the communication wavelength. The strongest resonance occurs at 1.2375 μm in the y-polarized case, and the peaking loss can reach 435.83 dB/cm.

关键词： photonic crystal fiber birefringence surface plasmon

Mode splitting of a cavity with a high-density birefringence rubidium vapor in the superstrong coupling regime

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Science China(Physics,Mechanics & Astronomy) 2014年第7期57卷 1283-1288页

作者： CHEN LiangChao YU XuDong MENG ZengMing ZHANG Jing State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-ElectronicsShanxi University

The mode splitting in a system with Doppler-broadened high-density two-level atoms in the presence of magnetic field inside a relatively long optical cavity is studied in the superstrong coupling regime(atoms-cavity coupling strength g√N is near or larger than the cavity free-spectral range?FSR).The effect of a magnetic field applied along the quantization axis is used to break the polarization degeneracy of the cavity and thereby introduce birefringence(or Faraday rotation)into the *** cavity modes are further split in the presence of the magnetic field compared with the normal case of the multi-normal-mode splitting of the two-level system near the D2 line *** dependence of the mode splitting on the magnetic field and the temperature is *** theoretical analysis according to the linear dispersion theory can provide a good explanation.

关键词： superstrong coupling normal-mode splitting Zeeman effect birefringence