A theoretical model of relationship between subsurface damage and surface roughness was established to realize rapid and non-destructive measurement of subsurface damage of ground optical materials.Postulated conditio...A theoretical model of relationship between subsurface damage and surface roughness was established to realize rapid and non-destructive measurement of subsurface damage of ground optical materials.Postulated condition of the model was that subsurface damage depth and peak-to-valley surface roughness are equal to depth of radial and lateral cracks in brittle surface induced by small-radius(radius≤200 μm)spherical indenter,respectively.And contribution of elastic stress field to the radial cracks propagation was also considered in the loading cycle.Subsurface damage depth of ground BK7 glasses was measured by magnetorheological finishing spot technique to validate theoretical ratio of subsurface damage to surface roughness.The results show that the ratio is directly proportional to load of abrasive grains and hardness of optical materials,while inversely proportional to granularity of abrasive grains and fracture toughness of optical materials.Moreover,the influence of the load and fracture toughness on the ratio is more significant than the granularity and hardness,respectively.The measured ratios of 80 grit and 120 grit fixed abrasive grinding of BK7 glasses are 5.8 and 5.4,respectively.展开更多
we have synthesised a series of new optically nonlinear organic materials of cinnamylidene-acetophenone derivatives which have large nonl inear optical susceptibilities and short cut-off wavelengths.
hydroxy-4-nitro azobenzene (NHA) and 4-amino-4-nitro azobenzene (DO3) were prepared respectively from p-nitrophenylamine as a precursor compound. Two kinds of doped organic/inorganic hybrid nonlinear optical (NLO) mat...hydroxy-4-nitro azobenzene (NHA) and 4-amino-4-nitro azobenzene (DO3) were prepared respectively from p-nitrophenylamine as a precursor compound. Two kinds of doped organic/inorganic hybrid nonlinear optical (NLO) materials containing NHA and DO3 were synthesized by Sol-Gel process. The preparation and properties of two NLO materials were studied and characterized by FTIR, 1H-NMR, UV-VIS, SEM, DSC and SHG measurements. The results show that the maximum doping amounts of NHA and DO3 in two doped hybrid NLO materials are 7.2(wt)% and 11.3(wt)% respectively, and the corresponding second-order NLO coefficients (d33 values) are 2.91×10 8esu and 6.14×10 8esu. Two doped NLO materials have relatively good RT stability, after 90 days at RT the d33 values can maintain about 85% of their initial values, but after 10h at 100℃ can only maintain about 50% of their initial values. In this report, the reasons for high-temperature instability of doped materials were discussed, and the possible improvements were also suggested.展开更多
Bluelightning Optics Co.,Ltd.(BOC)；The Featured of BOC's Nd:YLF:；Juhua Group Xinghua Crystal Materials Factory；Fujian Castech Crystals, Inc. (CASTECH)；Shanghai Fanguang Industry and Commerce Co.
To rationalize the design of D-π-A type organic small-molecule nonlinear optical materials,a theory guided machine learning framework is constructed.Such an approach is based on the recognition that the optical prope...To rationalize the design of D-π-A type organic small-molecule nonlinear optical materials,a theory guided machine learning framework is constructed.Such an approach is based on the recognition that the optical property of the molecule is predictable upon accumulating the contribution of each component,which is in line with the concept of group contribution method in thermodynamics.To realize this,a Lewis-mode group contribution method(LGC)has been developed in this work,which is combined with the multistage Bayesian neural network and the evolutionary algorithm to constitute an interactive framework(LGC-msBNN-EA).Thus,different optical properties of molecules are afforded accurately and efficientlyby using only a small data set for training.Moreover,by employing the EA model designed specifically for LGC,structural search is well achievable.The origins of the satisfying performance of the framework are discussed in detail.Considering that such a framework combines chemical principles and data-driven tools,most likely,it will be proven to be rational and efficient to complete mission regarding structure design in related fields.展开更多
Metal iodates containing I(Ⅴ)with lone electron pairs in an asymmetric coordination geometry exhibit excellent second-harmonic generation(SHG)responses,wide transmission range and large band gaps.During the past ten ...Metal iodates containing I(Ⅴ)with lone electron pairs in an asymmetric coordination geometry exhibit excellent second-harmonic generation(SHG)responses,wide transmission range and large band gaps.During the past ten years,metal iodates have been widely studied,and introducing large electronegative fluorine atoms into metal iodates has also attracted much attention.These F-containing iodates are different from pure iodates in terms of composition,symmetry and transmittance.Especially because oxide-fluoride heterolepic anion groups can exhibit interesting structure-directing properties,e.g.trans-and cis-directing properties,these F-containing iodates also have better structure designability.Therefore,in this review,we will review the research progress of F-containing iodates and address the effect of structure-directing properties of oxide-fluoride anions on the crystal structures of F-containing iodates.Since the valence of the central cations will greatly affect the distortions and configurations of the oxide-fluoride anion groups,these F-containing iodates will be classified and introduced according to the different valences of the central cations.展开更多
Nonlinear optical(NLO)material are of great importance in converting the frequency to extend the laser spectrum in mid-and far-infrared(IR)regions where lasers operate poorly or are unavailable.However,the contradicti...Nonlinear optical(NLO)material are of great importance in converting the frequency to extend the laser spectrum in mid-and far-infrared(IR)regions where lasers operate poorly or are unavailable.However,the contradiction between large second-harmonic generation(SHG)intensity and wide band gap(E_(g))is a long-standing problem for IR NLO materials.To address the issue,metal chalcogenides have been successfully synthesized and developed excellent optical properties in the past few decades.As a newly discovered category of chalcogenides,salt-inclusion chalcogenides with distinctive structures and brilliant performances have been placed great expecta-tions to be a novel problem-solving.In this review,52 compounds in this thriving family are categorized via dimensions of host and guest parts,further discussing the relationships between their structures and NLO properties,as well as future perspectives of this family.展开更多
Exploration of new infrared(IR) nonlinear optical(NLO) materials is still in urgency owing to the indispensable roles in optoelectronic devices, resource exploration, and long-distance laser communication. The formida...Exploration of new infrared(IR) nonlinear optical(NLO) materials is still in urgency owing to the indispensable roles in optoelectronic devices, resource exploration, and long-distance laser communication. The formidable challenge is to balance the contradiction between wide band gaps and large second harmonic generation(SHG) effects in IR NLO materials. In the present work, we proposed new kinds of NLO active units, d^0 transition metal fluorooxofunctional groups for designing mid-IR NLO materials. By studying a series of d^0 transition metal oxyfluorides(TMOFs),the influences of fluorooxo-functional groups with different d^0 configuration cations on the band gap and SHG responses were explored. The results reveal that the fluorooxo-functional groups with different d^0 configuration cations can enlarge band gaps in mid-IR NLO materials. The first-principles calculations demonstrate that the nine alkali/alkaline earth metals d^0 TMOFs exhibit wide band gaps(all the band gaps >3.0 e V), large birefringence Δn(> 0.07), and two W/Mo TMOFs also exhibit large SHG responses. Moreover, by comparing with other fluorooxo-functional groups, it is found that introducing fluorine into building units is an effective way to enhance optical performance. These d^0 TMOFs with superior fluorooxo-functional groups represent a new exploration family of the mid-IR region, which sheds light on the design of mid-IR NLO materials possessing large band gap.展开更多
Three new complex borate compounds K7CaBi2B15O30, K7CaLa2B15 O30 and K7BaBi2B15O30 have been synthesized by the high-temperature solution method.K7CaLa2B15O30and K7CaBi2B15O30crystallize in the chiral trigonal space g...Three new complex borate compounds K7CaBi2B15O30, K7CaLa2B15 O30 and K7BaBi2B15O30 have been synthesized by the high-temperature solution method.K7CaLa2B15O30and K7CaBi2B15O30crystallize in the chiral trigonal space group R32, while K7BaBi2B15O30 crystallizes in the noncentrosymmetric orthorhombic polar space group Pca21. All of the title compounds have similar three-dimensional crystal structures, which are composed of isolated B5 O10 groups and LaO6 or BiO6 octahedra, and K^+, Ca^2+, and Ba^2+ cations fill into the cavities to keep charge balance. Based on our research, in the system of K7 MIIRE2 B15O30(MII= Ca, Sr,Ba, Zn, Cd, Pb, K/RE0.5;RE = Sc, Y, La, Gd, Lu, Bi),K7BaBi2B15O30 is unique and crystallizes in a different space group, which enriches the structural chemistry of borate.Detailed structural analyses indicate that the structural variation is due to the difference in size and coordination number of the alkaline-earth metal cations. Besides, UV-Vis-NIR spectroscopy analysis and the second-harmonic generation(SHG) measurement on the powder samples show that K7CaBi2B15O30 exhibits a UV cutoff edge(about 282 nm) and a moderate SHG response(about 0.6 × KDP). In addition,thermal analysis and infrared spectroscopy were also presented. To better understand the structure-property relationships of the title compounds, the first-principles calculations have been performed.展开更多
The nonlinear optical （NLO） and optical limiting （OL） properties of three new structures of organic NLO guest host Poly（N-vinylcarbozole）/disperse orange 3 （PVK/DO3）, PVK/disperse orange 13 （PVK/DO13）. and P...The nonlinear optical （NLO） and optical limiting （OL） properties of three new structures of organic NLO guest host Poly（N-vinylcarbozole）/disperse orange 3 （PVK/DO3）, PVK/disperse orange 13 （PVK/DO13）. and PVK/disperse orange 25 （PVK/DO25） as a solution at different concentrations and as a thin-film sample are studied using continuous wave z-scan system at 532 nm. The open-aperture z-scan data of the NLO materials in the solution and thin-film samples displayed two-photon and saturable absorptions, respectively. The PVK/DO13 exhibites the largest and best values of the nonlinearities, such as n2, β, X（3） compared with those of PVK/DO3 and PVK/DO25. This nonlinearity increases as the concentration increases. Tile results indicate that these NLO materials are good candidates for optical switching and OL devices.展开更多
Ultraviolet(UV)nonlinear optical(NLO)crystal materials are hailed as the"chip"of the optoelectronic industry for they play a unique and crucial role in many newly developed scientific and technological appli...Ultraviolet(UV)nonlinear optical(NLO)crystal materials are hailed as the"chip"of the optoelectronic industry for they play a unique and crucial role in many newly developed scientific and technological applications.At present,due to the relatively single frequency doubling gene types of traditional NLO materials,the service performance of UV NLO materials is fundamentally restricted.Therefore,there is an urgent need to develop new synthesis methods,search for novel functional groups,expand new UV NLO materials systems,screen new high-performance crystals,and then break through performance bottlenecks.Herein,we review the recent progresses on UV NLO crystal materials.Furthermore,we prospect that these recently developed approaches will continuously extend their advantages in developing superior UV NLO materials in the near future.展开更多
We report a simple solution-processed method for the fabrication of low-cost,flexible optical limiting materials based on graphene oxide(GO) impregnated polyvinyl alcohol(PVA) sheets.Such GO–PVA composite sheets disp...We report a simple solution-processed method for the fabrication of low-cost,flexible optical limiting materials based on graphene oxide(GO) impregnated polyvinyl alcohol(PVA) sheets.Such GO–PVA composite sheets display highly efficient broadband optical limiting activities for femtosecond laser pulses at 400,800,and 1400 nm with very low limiting thresholds.Femtosecond pump–probe measurement results revealed that nonlinear absorption played an important role for the observed optical limiting activities.High flexibility and efficient optical limiting activities of these materials allow these composite sheets to be attached to nonplanar optical sensors in order to protect them from light-induced damage.展开更多
Faraday effect measurements of holmium oxide(Ho_2O_3) ceramics-based magneto-optical materials, highly potential material candidates for high-energy laser Faraday isolators, are presented in this paper. Temperature de...Faraday effect measurements of holmium oxide(Ho_2O_3) ceramics-based magneto-optical materials, highly potential material candidates for high-energy laser Faraday isolators, are presented in this paper. Temperature dependence of the Verdet constant of nondoped Ho_2O_3 ceramics was measured for temperatures 15–305 K at 1.064 μm wavelength.The Verdet constant dispersion for wavelengths 0.5–1 μm and 1.064 μm was measured for both nondoped Ho_2O_3 ceramics and Ho_2O_3 ceramics doped with terbium Tb3+(0.2 at. %) and cerium Ce3+(0.1 at. %) ions. The results suggest that the relatively low level of doping of Ho_2O_3 with these ions has no significant boosting impact on the Faraday effect. Therefore, other compositions of Ho_2O_3 ceramics-based magneto-optical materials, as well as various doping concentrations, should be further examined.展开更多
Cholesteric liquid crystals（CLCs） have recently sparked an enormous amount of interest in the development of soft matter materials due to their unique ability to self-organize into a helical supra-molecular architec...Cholesteric liquid crystals（CLCs） have recently sparked an enormous amount of interest in the development of soft matter materials due to their unique ability to self-organize into a helical supra-molecular architecture and their excellent selective reflection of light based on the Bragg relationship.Nowadays,by the virtue of building the self-organized nanostructures with pitch gradient or non-uniform pitch distribution,extensive work has already been performed to obtain CLC films with a broad reflection band.Based on authors＇ many years＇ research experience,this critical review systematically summarizes the physical and optical background of the CLCs with broadband reflection characteristics,methods to obtain broadband reflection of CLCs,as well as the application in the field of intelligent optical modulation materials.Combined with the research status and the advantages in the field,the important basic and applied scientific problems in the research direction are also introduced.展开更多
We study optical localized waves on a plane-wave background in negative-index materials governed by the defocusing nonlinear Schr6dinger equation with self-steepening effect. Important characteristics of localized wav...We study optical localized waves on a plane-wave background in negative-index materials governed by the defocusing nonlinear Schr6dinger equation with self-steepening effect. Important characteristics of localized waves, such as the excitations, transitions, propagation stability, and mechanism, are revealed in detail. An intrigu- ing sequential transition that involves the rogue wave, antidark-dark soliton pair, antidark soliton and antidark soliton pair can be triggered as the self-steepening effect attenuates. The corresponding phase diagram is estab- lished in the defocusing regime of negative-index materials. The propagation stability of the localized waves is confirmed numerically. In particular, our results illuminate the transition mechanism by establishing the exact correspondence between the transition and the modulation instability analysis.展开更多
AgGa_(1-x)In_(x)Se_(2)polycrystals were synthesized by the method of mechanical oscillation and temperature oscillation.X-ray diffraction spectra of polycrystal powder are conformable with the JCPDS cards.Lattice cons...AgGa_(1-x)In_(x)Se_(2)polycrystals were synthesized by the method of mechanical oscillation and temperature oscillation.X-ray diffraction spectra of polycrystal powder are conformable with the JCPDS cards.Lattice constants a and c calculated from the XRD were found to obey Vegard's law.The melting point of AgGa_(0.8)In_(0.2)Se_(2)obtained by means of differential scanning calorimetry(DSC)is 796.53℃.The DSC curve also show that there are no other transformation points below the melting point.The results indicate that polycrystalline materials synthesized by the method mentioned above are high-quality and can be used to grow single crystals by the vertical Bridgman technology.展开更多
Q-switched lasers have occupied important roles in industrial applications such as laser marking,engraving,welding,and cutting due to their advantages in high pulse energy.Here,SnS_(2)-based Q-switched lasers are impl...Q-switched lasers have occupied important roles in industrial applications such as laser marking,engraving,welding,and cutting due to their advantages in high pulse energy.Here,SnS_(2)-based Q-switched lasers are implemented.Consid-ering that SnS_(2) inherits the thickness sensitive optical characteristics of TMD,three kinds of SnS2 with different thick-ness are characterized in terms of nonlinearity and used to realize the Q-switched pulses under consistent implementa-tion conditions for comparison tests.According to the results,the influence of thickness variation on the nonlinear per-formance of saturable absorber,such as modulation depth and absorption intensity,and the influence on the correspond-ing laser are analyzed.In addition,compared with other traditional saturable absorbers,the advantage of SnS_(2) in realiz-ing ultrashort pulses is also noticed.Our work explores the thickness-dependent nonlinear optical properties of SnS_(2),and the rules found is of great reference value for the establishment of target lasers.展开更多
3-Ethynyl-4-(trimethylsilyl)thiophene (1a) and 3-ethynyl-4-bromothiophene (1b) selectively undergo acetylene polymerizations in the presence of the MoCl5- and WCl6-Ph3SiH catalysts to give soluble, high-molecular-weig...3-Ethynyl-4-(trimethylsilyl)thiophene (1a) and 3-ethynyl-4-bromothiophene (1b) selectively undergo acetylene polymerizations in the presence of the MoCl5- and WCl6-Ph3SiH catalysts to give soluble, high-molecular-weight poly(thienylacetylenes) (2) (M-w up to 602000) in high yields (up to 100%). Light transmission spectra of THF solutions of 2 continuously red-shift with increasing concentration. The concentratochromism shows a logarithmic concentration dependence; that is, the optical transitions of 2 are predictably tunable by simply changing their concentrations.展开更多
基金Project(50375156) supported by the National Natural Science Foundation of China
文摘A theoretical model of relationship between subsurface damage and surface roughness was established to realize rapid and non-destructive measurement of subsurface damage of ground optical materials.Postulated condition of the model was that subsurface damage depth and peak-to-valley surface roughness are equal to depth of radial and lateral cracks in brittle surface induced by small-radius(radius≤200 μm)spherical indenter,respectively.And contribution of elastic stress field to the radial cracks propagation was also considered in the loading cycle.Subsurface damage depth of ground BK7 glasses was measured by magnetorheological finishing spot technique to validate theoretical ratio of subsurface damage to surface roughness.The results show that the ratio is directly proportional to load of abrasive grains and hardness of optical materials,while inversely proportional to granularity of abrasive grains and fracture toughness of optical materials.Moreover,the influence of the load and fracture toughness on the ratio is more significant than the granularity and hardness,respectively.The measured ratios of 80 grit and 120 grit fixed abrasive grinding of BK7 glasses are 5.8 and 5.4,respectively.
文摘we have synthesised a series of new optically nonlinear organic materials of cinnamylidene-acetophenone derivatives which have large nonl inear optical susceptibilities and short cut-off wavelengths.
基金Plan Project of Science and Technology of Guangzhou City (2002J1-C0061) The First Author: XI Hongxia(1968-)
文摘hydroxy-4-nitro azobenzene (NHA) and 4-amino-4-nitro azobenzene (DO3) were prepared respectively from p-nitrophenylamine as a precursor compound. Two kinds of doped organic/inorganic hybrid nonlinear optical (NLO) materials containing NHA and DO3 were synthesized by Sol-Gel process. The preparation and properties of two NLO materials were studied and characterized by FTIR, 1H-NMR, UV-VIS, SEM, DSC and SHG measurements. The results show that the maximum doping amounts of NHA and DO3 in two doped hybrid NLO materials are 7.2(wt)% and 11.3(wt)% respectively, and the corresponding second-order NLO coefficients (d33 values) are 2.91×10 8esu and 6.14×10 8esu. Two doped NLO materials have relatively good RT stability, after 90 days at RT the d33 values can maintain about 85% of their initial values, but after 10h at 100℃ can only maintain about 50% of their initial values. In this report, the reasons for high-temperature instability of doped materials were discussed, and the possible improvements were also suggested.
文摘Bluelightning Optics Co.,Ltd.(BOC)；The Featured of BOC's Nd:YLF:；Juhua Group Xinghua Crystal Materials Factory；Fujian Castech Crystals, Inc. (CASTECH)；Shanghai Fanguang Industry and Commerce Co.
基金support by the Key Research and Development Program of Zhejiang Province(2023C01102,2023C01208,2022C01208)。
文摘To rationalize the design of D-π-A type organic small-molecule nonlinear optical materials,a theory guided machine learning framework is constructed.Such an approach is based on the recognition that the optical property of the molecule is predictable upon accumulating the contribution of each component,which is in line with the concept of group contribution method in thermodynamics.To realize this,a Lewis-mode group contribution method(LGC)has been developed in this work,which is combined with the multistage Bayesian neural network and the evolutionary algorithm to constitute an interactive framework(LGC-msBNN-EA).Thus,different optical properties of molecules are afforded accurately and efficientlyby using only a small data set for training.Moreover,by employing the EA model designed specifically for LGC,structural search is well achievable.The origins of the satisfying performance of the framework are discussed in detail.Considering that such a framework combines chemical principles and data-driven tools,most likely,it will be proven to be rational and efficient to complete mission regarding structure design in related fields.
基金supported by the National Natural Science Foundation of China,China(Grant Nos.22071179,51902224,51972230,52172006,51890864,51890865)Natural Science Foundation of Tianjin,China(Grant Nos.20JCJQJC00060,21JCJQJC00090).
文摘Metal iodates containing I(Ⅴ)with lone electron pairs in an asymmetric coordination geometry exhibit excellent second-harmonic generation(SHG)responses,wide transmission range and large band gaps.During the past ten years,metal iodates have been widely studied,and introducing large electronegative fluorine atoms into metal iodates has also attracted much attention.These F-containing iodates are different from pure iodates in terms of composition,symmetry and transmittance.Especially because oxide-fluoride heterolepic anion groups can exhibit interesting structure-directing properties,e.g.trans-and cis-directing properties,these F-containing iodates also have better structure designability.Therefore,in this review,we will review the research progress of F-containing iodates and address the effect of structure-directing properties of oxide-fluoride anions on the crystal structures of F-containing iodates.Since the valence of the central cations will greatly affect the distortions and configurations of the oxide-fluoride anion groups,these F-containing iodates will be classified and introduced according to the different valences of the central cations.
基金supported by the National Natural Science Foundation of China(21921001,22075283,92161125,U21A20508)the Youth Innovation Promotion Association of Chinese Academy of Sciences of China(2021300)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2020ZZ108,2021ZR205).
文摘Nonlinear optical(NLO)material are of great importance in converting the frequency to extend the laser spectrum in mid-and far-infrared(IR)regions where lasers operate poorly or are unavailable.However,the contradiction between large second-harmonic generation(SHG)intensity and wide band gap(E_(g))is a long-standing problem for IR NLO materials.To address the issue,metal chalcogenides have been successfully synthesized and developed excellent optical properties in the past few decades.As a newly discovered category of chalcogenides,salt-inclusion chalcogenides with distinctive structures and brilliant performances have been placed great expecta-tions to be a novel problem-solving.In this review,52 compounds in this thriving family are categorized via dimensions of host and guest parts,further discussing the relationships between their structures and NLO properties,as well as future perspectives of this family.
基金supported by Tianshan Innovation Team Program (2018D14001)the National Natural Science Foundation of China (51922014 and 11774414)+2 种基金Shanghai Cooperation Organization Science and Technology Partnership Program (2017E01013)Xinjiang Program of Introducing High-Level Talents, Fujian Institute of Innovation, Chinese Academy of Sciences (FJCXY18010202)the Western Light Foundation of CAS (2017-XBQNXZ-B-006 and 2016QNXZ-B-9)
文摘Exploration of new infrared(IR) nonlinear optical(NLO) materials is still in urgency owing to the indispensable roles in optoelectronic devices, resource exploration, and long-distance laser communication. The formidable challenge is to balance the contradiction between wide band gaps and large second harmonic generation(SHG) effects in IR NLO materials. In the present work, we proposed new kinds of NLO active units, d^0 transition metal fluorooxofunctional groups for designing mid-IR NLO materials. By studying a series of d^0 transition metal oxyfluorides(TMOFs),the influences of fluorooxo-functional groups with different d^0 configuration cations on the band gap and SHG responses were explored. The results reveal that the fluorooxo-functional groups with different d^0 configuration cations can enlarge band gaps in mid-IR NLO materials. The first-principles calculations demonstrate that the nine alkali/alkaline earth metals d^0 TMOFs exhibit wide band gaps(all the band gaps >3.0 e V), large birefringence Δn(> 0.07), and two W/Mo TMOFs also exhibit large SHG responses. Moreover, by comparing with other fluorooxo-functional groups, it is found that introducing fluorine into building units is an effective way to enhance optical performance. These d^0 TMOFs with superior fluorooxo-functional groups represent a new exploration family of the mid-IR region, which sheds light on the design of mid-IR NLO materials possessing large band gap.
基金supported by the West Light Foundation of the CAS(2016-YJRC-2 and 2015 XBQN-B-11)the National Natural Science Foundation of China(51602341 and 91622107)+2 种基金the Natural Science Foundation of Xinjiang(2016D01B061)Tianshan Innovation Team Program(2018D14001)Key research project of Frontier Science of CAS(QYZDB-SSW-JSC049)
文摘Three new complex borate compounds K7CaBi2B15O30, K7CaLa2B15 O30 and K7BaBi2B15O30 have been synthesized by the high-temperature solution method.K7CaLa2B15O30and K7CaBi2B15O30crystallize in the chiral trigonal space group R32, while K7BaBi2B15O30 crystallizes in the noncentrosymmetric orthorhombic polar space group Pca21. All of the title compounds have similar three-dimensional crystal structures, which are composed of isolated B5 O10 groups and LaO6 or BiO6 octahedra, and K^+, Ca^2+, and Ba^2+ cations fill into the cavities to keep charge balance. Based on our research, in the system of K7 MIIRE2 B15O30(MII= Ca, Sr,Ba, Zn, Cd, Pb, K/RE0.5;RE = Sc, Y, La, Gd, Lu, Bi),K7BaBi2B15O30 is unique and crystallizes in a different space group, which enriches the structural chemistry of borate.Detailed structural analyses indicate that the structural variation is due to the difference in size and coordination number of the alkaline-earth metal cations. Besides, UV-Vis-NIR spectroscopy analysis and the second-harmonic generation(SHG) measurement on the powder samples show that K7CaBi2B15O30 exhibits a UV cutoff edge(about 282 nm) and a moderate SHG response(about 0.6 × KDP). In addition,thermal analysis and infrared spectroscopy were also presented. To better understand the structure-property relationships of the title compounds, the first-principles calculations have been performed.
文摘The nonlinear optical （NLO） and optical limiting （OL） properties of three new structures of organic NLO guest host Poly（N-vinylcarbozole）/disperse orange 3 （PVK/DO3）, PVK/disperse orange 13 （PVK/DO13）. and PVK/disperse orange 25 （PVK/DO25） as a solution at different concentrations and as a thin-film sample are studied using continuous wave z-scan system at 532 nm. The open-aperture z-scan data of the NLO materials in the solution and thin-film samples displayed two-photon and saturable absorptions, respectively. The PVK/DO13 exhibites the largest and best values of the nonlinearities, such as n2, β, X（3） compared with those of PVK/DO3 and PVK/DO25. This nonlinearity increases as the concentration increases. Tile results indicate that these NLO materials are good candidates for optical switching and OL devices.
基金Supported by National Natural Science Foundation of China(21971171,21875146)。
文摘Ultraviolet(UV)nonlinear optical(NLO)crystal materials are hailed as the"chip"of the optoelectronic industry for they play a unique and crucial role in many newly developed scientific and technological applications.At present,due to the relatively single frequency doubling gene types of traditional NLO materials,the service performance of UV NLO materials is fundamentally restricted.Therefore,there is an urgent need to develop new synthesis methods,search for novel functional groups,expand new UV NLO materials systems,screen new high-performance crystals,and then break through performance bottlenecks.Herein,we review the recent progresses on UV NLO crystal materials.Furthermore,we prospect that these recently developed approaches will continuously extend their advantages in developing superior UV NLO materials in the near future.
基金financial support from the Guangdong Innovative Research Team Program of China (201101C0105067115)DSTA Singapore (Project DSTA-NUS-DIRP/9010100347)National Research Foundation Singapore (R398-001-062-281)
文摘We report a simple solution-processed method for the fabrication of low-cost,flexible optical limiting materials based on graphene oxide(GO) impregnated polyvinyl alcohol(PVA) sheets.Such GO–PVA composite sheets display highly efficient broadband optical limiting activities for femtosecond laser pulses at 400,800,and 1400 nm with very low limiting thresholds.Femtosecond pump–probe measurement results revealed that nonlinear absorption played an important role for the observed optical limiting activities.High flexibility and efficient optical limiting activities of these materials allow these composite sheets to be attached to nonplanar optical sensors in order to protect them from light-induced damage.
基金supported by JSPS KAKENHI (Grant No. 15KK0245)the support and under the auspices of the National Institute for Fusion Science (KEIN1608)+3 种基金co-financed by the European Regional Development Fundthe state budget of the Czech Republic (project Hi LASE Co E: Grant No. CZ.02.1.010.00.015 0060000674)by the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 739573supported by the Ministry of Education, Youth and Sports of the Czech Republic (Programmes NPU I Project No. LO1602, and Large Research Infrastructure Project No. LM2015086)
文摘Faraday effect measurements of holmium oxide(Ho_2O_3) ceramics-based magneto-optical materials, highly potential material candidates for high-energy laser Faraday isolators, are presented in this paper. Temperature dependence of the Verdet constant of nondoped Ho_2O_3 ceramics was measured for temperatures 15–305 K at 1.064 μm wavelength.The Verdet constant dispersion for wavelengths 0.5–1 μm and 1.064 μm was measured for both nondoped Ho_2O_3 ceramics and Ho_2O_3 ceramics doped with terbium Tb3+(0.2 at. %) and cerium Ce3+(0.1 at. %) ions. The results suggest that the relatively low level of doping of Ho_2O_3 with these ions has no significant boosting impact on the Faraday effect. Therefore, other compositions of Ho_2O_3 ceramics-based magneto-optical materials, as well as various doping concentrations, should be further examined.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51573006,51573003,51203003,51303008,51302006,51402006,51272026,and 51273022)the Major Project of Beijing Science and Technology Program,China(Grant Nos.Z151100003315023 and Z141100003814011)the Fok Ying Tung Education Foundation,China(Grant No.142009)
文摘Cholesteric liquid crystals（CLCs） have recently sparked an enormous amount of interest in the development of soft matter materials due to their unique ability to self-organize into a helical supra-molecular architecture and their excellent selective reflection of light based on the Bragg relationship.Nowadays,by the virtue of building the self-organized nanostructures with pitch gradient or non-uniform pitch distribution,extensive work has already been performed to obtain CLC films with a broad reflection band.Based on authors＇ many years＇ research experience,this critical review systematically summarizes the physical and optical background of the CLCs with broadband reflection characteristics,methods to obtain broadband reflection of CLCs,as well as the application in the field of intelligent optical modulation materials.Combined with the research status and the advantages in the field,the important basic and applied scientific problems in the research direction are also introduced.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11475135,11547302,11434013 and 11425522
文摘We study optical localized waves on a plane-wave background in negative-index materials governed by the defocusing nonlinear Schr6dinger equation with self-steepening effect. Important characteristics of localized waves, such as the excitations, transitions, propagation stability, and mechanism, are revealed in detail. An intrigu- ing sequential transition that involves the rogue wave, antidark-dark soliton pair, antidark soliton and antidark soliton pair can be triggered as the self-steepening effect attenuates. The corresponding phase diagram is estab- lished in the defocusing regime of negative-index materials. The propagation stability of the localized waves is confirmed numerically. In particular, our results illuminate the transition mechanism by establishing the exact correspondence between the transition and the modulation instability analysis.
基金Project supported by the Specialized Research Fund for the Doctoral Program of Higher Education(20040610024)
文摘AgGa_(1-x)In_(x)Se_(2)polycrystals were synthesized by the method of mechanical oscillation and temperature oscillation.X-ray diffraction spectra of polycrystal powder are conformable with the JCPDS cards.Lattice constants a and c calculated from the XRD were found to obey Vegard's law.The melting point of AgGa_(0.8)In_(0.2)Se_(2)obtained by means of differential scanning calorimetry(DSC)is 796.53℃.The DSC curve also show that there are no other transformation points below the melting point.The results indicate that polycrystalline materials synthesized by the method mentioned above are high-quality and can be used to grow single crystals by the vertical Bridgman technology.
基金the financial support from the National Natural Science Foundation of China(11875008,12075034)Open Research Fund of State Key Laboratory of Pulsed Power Laser Technology(Grant SKL2019KF04)Fundamental Research Funds for the Central Universities(2019XD-A09-3).
文摘Q-switched lasers have occupied important roles in industrial applications such as laser marking,engraving,welding,and cutting due to their advantages in high pulse energy.Here,SnS_(2)-based Q-switched lasers are implemented.Consid-ering that SnS_(2) inherits the thickness sensitive optical characteristics of TMD,three kinds of SnS2 with different thick-ness are characterized in terms of nonlinearity and used to realize the Q-switched pulses under consistent implementa-tion conditions for comparison tests.According to the results,the influence of thickness variation on the nonlinear per-formance of saturable absorber,such as modulation depth and absorption intensity,and the influence on the correspond-ing laser are analyzed.In addition,compared with other traditional saturable absorbers,the advantage of SnS_(2) in realiz-ing ultrashort pulses is also noticed.Our work explores the thickness-dependent nonlinear optical properties of SnS_(2),and the rules found is of great reference value for the establishment of target lasers.
基金This work was in part supported by the Earmarked Research Grants of the Hong Kong Research Grants Council (HKUST597/95P and CUHK77/931).
文摘3-Ethynyl-4-(trimethylsilyl)thiophene (1a) and 3-ethynyl-4-bromothiophene (1b) selectively undergo acetylene polymerizations in the presence of the MoCl5- and WCl6-Ph3SiH catalysts to give soluble, high-molecular-weight poly(thienylacetylenes) (2) (M-w up to 602000) in high yields (up to 100%). Light transmission spectra of THF solutions of 2 continuously red-shift with increasing concentration. The concentratochromism shows a logarithmic concentration dependence; that is, the optical transitions of 2 are predictably tunable by simply changing their concentrations.
