A novel torsion sensor,which can be embedded in the engineering material,is proposed.Based on the coupled mode theory and the characteristic of twisted high birefringence fiber,we have established the mathematical mod...A novel torsion sensor,which can be embedded in the engineering material,is proposed.Based on the coupled mode theory and the characteristic of twisted high birefringence fiber,we have established the mathematical model of twisted high birefringence fiber grating transfer matrix.Two numerical simulation methods based on the transfer matrix method and coupled mode theory were used to analyze the consequent changes in reflection spectra.The simulation results of the two methods show good agreement with each other.The two main peak wavelengths of the high birefringence fiber grating shift as the twist angle changes from 0 to 360.And a peak was produced among the wavelengths of two main peaks.Its wavelength basically does not change and is about 1 552.225 nm.Its corresponding reflected peak value R_c basically presents the linear relationship with the twist angle α.The experiments show that the system has a wide measurement range.The resolution is 0.012° and the sensitivity is 0.13/rad.Good agreements between experimental results and numerical simulations have been obtained.展开更多
[PO_(4)]3-possesses small microscopic secondorder susceptibility and polarizability anisotropy,which inherently result in weak second-harmonic generation (SHG)and small birefringence.Herein,a new noncentrosymmetric ph...[PO_(4)]3-possesses small microscopic secondorder susceptibility and polarizability anisotropy,which inherently result in weak second-harmonic generation (SHG)and small birefringence.Herein,a new noncentrosymmetric phosphate,[C(NH_(2))3]3PO_(4)·2H_(2)O,was successfully designed and synthesized by a solution evaporation method.[C(NH_(2))3]3PO_(4)·2H_(2)O without metal ions is composed of planar conjugated guanidine cations and PO_(4)tetrahedrons,which are connected by hydrogen bonds,forming a three-dimensional network.Physical property measurements indicate that the title compound displays an SHG response of 1.5×KH_(2)PO_(4)(KDP) and a larger birefringence (0.055@546.1 nm)compared with most reported ultraviolet nonlinear optical phosphates.Furthermore,first-principles calculations reveal that theπ-conjugated planar[C(NH_(2))3]+cations and[PO_(4)]3-groups are responsible for its excellent linear and NLOproperties.展开更多
Wide transmittance range is an essential factor for the design of infrared optical materials.Traditionally,the designs of mid-far infrared crystals have focused on oxygenfree systems of chalcogenides and pnictides.Nev...Wide transmittance range is an essential factor for the design of infrared optical materials.Traditionally,the designs of mid-far infrared crystals have focused on oxygenfree systems of chalcogenides and pnictides.Nevertheless,the introduction of elements with large atomic numbers,such as the lone-pair cation Pb^(2+) and halogen anion I^(-),based on the oxyhalides,can broaden the infrared transmittance range.Thus,two new polymorphs of Pb(Ⅱ)-containing oxyhalides,Pb_(14)O_(8)I_(12)(α-POI)and Pb_(7)O_(4)I_(6)(β-POI),are successfully synthesized via the high-temperature solution method.Interestingly,they crystallize in the same space group,P1,and present unprecedented[O_(8)Pb_(14)]clusters from the perspective of oxocentered[OPb_(4)]basic units.Remarkably,POI exhibits a quite wide transparent range(0.47-16.0μm),which enlightens the oxyhalides with prominent infrared optical properties.Additionally,the first principles calculations show that they have large birefringence(0.139 and 0.108 for α-and β-POI at 1064 nm,respectively),which makes POI promising infrared optical materials.展开更多
基金Supported by National Natural Science Foundation of China(60377002)
文摘A novel torsion sensor,which can be embedded in the engineering material,is proposed.Based on the coupled mode theory and the characteristic of twisted high birefringence fiber,we have established the mathematical model of twisted high birefringence fiber grating transfer matrix.Two numerical simulation methods based on the transfer matrix method and coupled mode theory were used to analyze the consequent changes in reflection spectra.The simulation results of the two methods show good agreement with each other.The two main peak wavelengths of the high birefringence fiber grating shift as the twist angle changes from 0 to 360.And a peak was produced among the wavelengths of two main peaks.Its wavelength basically does not change and is about 1 552.225 nm.Its corresponding reflected peak value R_c basically presents the linear relationship with the twist angle α.The experiments show that the system has a wide measurement range.The resolution is 0.012° and the sensitivity is 0.13/rad.Good agreements between experimental results and numerical simulations have been obtained.
基金supported by the National Natural Science Foundation of China (21975255,51890862,21921001 and U1605245)the National Key Research and Development Plan of Ministry of Science and Technology (2016YFB0402104)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB20000000)the Natural Science Foundation of Fujian Province (2019J01020758)Youth Innovation Promotion Association CAS (2019303)。
文摘[PO_(4)]3-possesses small microscopic secondorder susceptibility and polarizability anisotropy,which inherently result in weak second-harmonic generation (SHG)and small birefringence.Herein,a new noncentrosymmetric phosphate,[C(NH_(2))3]3PO_(4)·2H_(2)O,was successfully designed and synthesized by a solution evaporation method.[C(NH_(2))3]3PO_(4)·2H_(2)O without metal ions is composed of planar conjugated guanidine cations and PO_(4)tetrahedrons,which are connected by hydrogen bonds,forming a three-dimensional network.Physical property measurements indicate that the title compound displays an SHG response of 1.5×KH_(2)PO_(4)(KDP) and a larger birefringence (0.055@546.1 nm)compared with most reported ultraviolet nonlinear optical phosphates.Furthermore,first-principles calculations reveal that theπ-conjugated planar[C(NH_(2))3]+cations and[PO_(4)]3-groups are responsible for its excellent linear and NLOproperties.
基金supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences(CAS)(2020429)the National Natural Science Foundation of China(22122509,52002398 and 11774414)+3 种基金the West Light Foundation of the CAS(2019-YDYLTD-002)the International Partnership Program of CAS(1A1365KYSB20200008)the Instrument Developing Project of CAS(GJJSTD20200007)the Science and Technology Service Network Initiative of CAS(KFJ-STS-QYZD-130)。
文摘Wide transmittance range is an essential factor for the design of infrared optical materials.Traditionally,the designs of mid-far infrared crystals have focused on oxygenfree systems of chalcogenides and pnictides.Nevertheless,the introduction of elements with large atomic numbers,such as the lone-pair cation Pb^(2+) and halogen anion I^(-),based on the oxyhalides,can broaden the infrared transmittance range.Thus,two new polymorphs of Pb(Ⅱ)-containing oxyhalides,Pb_(14)O_(8)I_(12)(α-POI)and Pb_(7)O_(4)I_(6)(β-POI),are successfully synthesized via the high-temperature solution method.Interestingly,they crystallize in the same space group,P1,and present unprecedented[O_(8)Pb_(14)]clusters from the perspective of oxocentered[OPb_(4)]basic units.Remarkably,POI exhibits a quite wide transparent range(0.47-16.0μm),which enlightens the oxyhalides with prominent infrared optical properties.Additionally,the first principles calculations show that they have large birefringence(0.139 and 0.108 for α-and β-POI at 1064 nm,respectively),which makes POI promising infrared optical materials.
