Two new isostructural multi-metal beryllium borates, m^3 Li Na4Be4B10O24F（M = Sr（1）, Cd（2））, have been synthesized by spontaneous crystallization. The structures were verified by single-crystal X-ray crystallogr...Two new isostructural multi-metal beryllium borates, m^3 Li Na4Be4B10O24F（M = Sr（1）, Cd（2））, have been synthesized by spontaneous crystallization. The structures were verified by single-crystal X-ray crystallography. The compounds crystallize in the trigonal space group R 3, with a = b = 9.4645（1） A, c = 38.842（8） A, V = 3013.2（6） A3, Z = 6, F（000） = 2568, Dc = 3.005 g/cm^3, Mr = 908.9, R = 0.0327, w R = 0.0678, μ = 8.160 mm-1 for Sr3 Li Na4Be4B10O24F and a = b = 9.3019（8） A, c = 37.782（7） A, V = 2831.12（9） A3, Z = 6, F（000） = 2748, Dc = 3.459 g/cm^3, Mr = 983.24, R = 0.0158, w R = 0.0455, μ = 3.586 mm-1 for Cd3 Li Na4Be4B10O24F. The structures are characterized by an infinite two-dimensional [Be8B16O40F2]∞ double layer bridged by [B12O24] groups like a sandwich structure, while the cations reside in tunnels along different directions. UV-vis-IR diffuse reflectance spectroscopy demonstrates that their cut-off edges are below 200 nm. Thermal analysis shows that they melt incongruently and their melting points are around 740-770 ℃.展开更多
Pr3+ doped La2CaB10O19 crystal were grown by the top-seeded solution growth(TSSG) method.The absorption spectra,emission spectra and lifetime were measured at room temperature.The J-O parameters(Ωt,t=2,4,6),the radia...Pr3+ doped La2CaB10O19 crystal were grown by the top-seeded solution growth(TSSG) method.The absorption spectra,emission spectra and lifetime were measured at room temperature.The J-O parameters(Ωt,t=2,4,6),the radiative transition probabilities AJ,J ,oscillator strengths PJ,J ,radiative lifetime τ,fluorescence branch ratios βJ and the value of integrated emission cross section have also been calculated.Five main absorption bands,3H4 to 3P1+3P2,3P0,1D2,3F3 + 3F4 and 3F2,were observed in the absorption spect...展开更多
Polycrystalline nano-sized neodymium doped yttrium aluminum garnet (Nd∶Y3Al5O12, Nd∶YAG) powders were synthesized via a gel combustion method using nitrates and citric acid as starting materials. The evolution of ph...Polycrystalline nano-sized neodymium doped yttrium aluminum garnet (Nd∶Y3Al5O12, Nd∶YAG) powders were synthesized via a gel combustion method using nitrates and citric acid as starting materials. The evolution of phase composition and micro-structure of the powders were characterized by X-ray powder diffraction, thermogravimetry/differential thermal analysis and scanning electron microscopy. Well-crystallized Nd∶YAG nano-sized powders could be obtained at 950 ℃ for 2 h. The resultant powders are well dispersed, have a relatively narrow size distribution with an average particle size of approximately 50 nm, and show excellent sinterability. These powders can be densified to 99.2% of the theoretical density by HP sintering at 1700 ℃ for 3 h under 20 MPa nitrogen pressure.展开更多
LaOsSi3 single crystals are synthesized for the first time by an arc melting method. The crystal features a tetrag- onal BaNiSn3-type structure （space group 14mm） which lacks inversion symmetry along the crystallogr...LaOsSi3 single crystals are synthesized for the first time by an arc melting method. The crystal features a tetrag- onal BaNiSn3-type structure （space group 14mm） which lacks inversion symmetry along the crystallographic c axis and is isostructural with the intensively studied Rashba-type noncentrosymmetric superconductors LaRhSi3 and LaIrSi3. Un- like LaRhSi3 and LaIrSi3 displaying superconductivity, LaOsSi3 shows only metallic behavior over the measured temper- ature range of 2 K-300 K. The Sommerfeld coefficient ]/derived from specific heat is 5.76 mJ.mol-1 -K-2, indicating that LaOsSi3 has a weak electronic correlation effect. The absence of superconductivity in LaOsSi3 may lie in the Os 5d bands in the electronic structure. If it is true, it would be useful to provide complementary knowledge in understanding the relation between conduction and the d bands of M in LaMSi3 compounds （M = transition metals）.展开更多
A special prism coupling technique with the KBe_(2)BO_(3)F_(2) crystal is adopted to produce deep ultraviolet light including the fourth harmonic from an Nd:YAG laser,for which a conversion efficiency as high as 10%ha...A special prism coupling technique with the KBe_(2)BO_(3)F_(2) crystal is adopted to produce deep ultraviolet light including the fourth harmonic from an Nd:YAG laser,for which a conversion efficiency as high as 10%has been obtained.展开更多
High-average-power fourth-harmonic generation (4thHG) of an Nd:YAG laser is achieved with a RbBe_(2)BO_(3)F_(2) (RBBF) costal.A maximum output power of 3 W at 266nm is obtained.To our knowledge,this is the first time ...High-average-power fourth-harmonic generation (4thHG) of an Nd:YAG laser is achieved with a RbBe_(2)BO_(3)F_(2) (RBBF) costal.A maximum output power of 3 W at 266nm is obtained.To our knowledge,this is the first time that efficient 4th HG is realized with RBBF.The angular bandwidth of 4th HG is also measured.展开更多
Single crystals of LiY6O5（BO3）3 were obtained by the flux method and its structure was determined by a four-circle automatic diffractometer with a MoKα radiation. It crystallizes in monoclinic, space group P21/n wi...Single crystals of LiY6O5（BO3）3 were obtained by the flux method and its structure was determined by a four-circle automatic diffractometer with a MoKα radiation. It crystallizes in monoclinic, space group P21/n with a = 8.330（3）, b = 15.444（4）, c = 8.780（3）°A,β = 91.85（3）°, V = 1129.0（6）°A^3, Z = 4, Mr= 796.83, F（000） = 1456, μ = 30.567 mm^-1, Dc= 4.688 g/cm^3, the final R = 0.0722 and wR = 0.1304. It exhibits a three-dimensional fiamework of yttrium-oxygen polyhedra interconnected by common edges and corners. B and Li atoms are located in the planes and cavities formed by oxygen atoms, respectively.展开更多
The barocaloric effect is considered as one of the most promising refrigeration with the potential to replace traditional gas compression refrigeration.One of the main obstacles to the application of barocaloric mater...The barocaloric effect is considered as one of the most promising refrigeration with the potential to replace traditional gas compression refrigeration.One of the main obstacles to the application of barocaloric materials lies in the requirement for high driving pressures.In this paper,we report on the barocaloric effect of Pb_(3)(VO_(4))_(2),which exhibits a ferroelastic transition from a high-temperature trigonal structure to a low-temperature monoclinic structure at 357 K,accompanied by a substantial volume change.The entropy change induced by hydrostatic pressure can reach up 14 J·kg^(-1)·K^(-1)under a relatively low pressure of 80 MPa.This work is expected to expand the selection range of barocaloric materials.展开更多
Tetraethylenepentamine(C8H23N5,TEPA) has been used as a novel precipitant to synthesize yttrium aluminum garnet(Y3Al5O12,YAG) precursor from a mixed solution of aluminum and yttrium nitrates via a normal-strike co-pre...Tetraethylenepentamine(C8H23N5,TEPA) has been used as a novel precipitant to synthesize yttrium aluminum garnet(Y3Al5O12,YAG) precursor from a mixed solution of aluminum and yttrium nitrates via a normal-strike co-precipitation method without controlling the pH value during precipitation process.The original precursor was analyzed by thermogravimetry/differential scanning calorimetry(TG/DSC).The evolution of phase composition and micro-structure of the as-synthesized YAG powders were characterized by X-ray ...展开更多
1.Introduction Inorganic borate crystals have received considerable attention in many applications as nonlinear optical(NLO)crystals,birefringence crystals and scintillator materials[1-3].Recently,it is a well-known s...1.Introduction Inorganic borate crystals have received considerable attention in many applications as nonlinear optical(NLO)crystals,birefringence crystals and scintillator materials[1-3].Recently,it is a well-known strategy for designing new NLO materials by utilizing NLO-active units.展开更多
We synthesized a potassium gadolinium phosphate K3Gd(PO_(4))_(2)with monoclinic structure(P2_(1/m))by the high-temperature solid-state reaction method.Its lattice constants obtained by Rietveld refinements of XRD curv...We synthesized a potassium gadolinium phosphate K3Gd(PO_(4))_(2)with monoclinic structure(P2_(1/m))by the high-temperature solid-state reaction method.Its lattice constants obtained by Rietveld refinements of XRD curve are a=0.7411 nm,b=0.5624 nm,and c=0.9433 nm.Magnetic and magnetocaloric properties of K_(3)Gd(PO_(4))_(2)were investigated in detail.The magnetic phase transition temperature of K3Gd(PO_(4))2 was determined by ultra-low temperature testing to be 0.58 K.K_(3)Gd(PO_(4))2 exhibits large magnetic entropy changes(-ΔSM).The maximum-ΔSM are 20.2 and 29.4 J/(kg·K)in the magnetic field variation(ΔH)of 1 and 2 T,respectively,which are larger than that of the commercial Gd_(3)Ga_(5)O_(12)(GGG).The maximum adiabatic temperature change(ΔT_(ad))reaches 5.91 K under a magnetic field change(ΔH)of 1 T.K_(3)Gd(PO_(4))_(2)is a potential magnetic refrigeration material for obtaining sub-Kelvin temperatures.展开更多
Nonlinear frequency conversion of wavelength agile and high-power random fiber lasers can provide a promising way to generate continuous-wave(CW)visible and mid-infrared(MIR)light with unique properties such as the co...Nonlinear frequency conversion of wavelength agile and high-power random fiber lasers can provide a promising way to generate continuous-wave(CW)visible and mid-infrared(MIR)light with unique properties such as the continuous modeless spectrum,low temporal/spatial coherence,and high temporal stability.Here,we report a dual-wavelength switchable and tunable random Raman fiber laser(RRFL)based on a phosphosilicate fiber that has two Raman gain peaks for the first time and demonstrate its superior capability to generate widely tunable CW visible and mid-infrared light via nonlinear frequency conversions.By using the combination of a tunable pump and two tunable gratings in Littrow configuration that can provide separated point feedback for the two Stokes wavelengths corresponding to silica-and phosphorus-related Raman peaks,the spectrum of an RRFL can be flexibly manipulated for the aim of nonlinear frequency conversions,including single-wavelength tunable emission at the 1.1μm or 1.2μm band for second-harmonic generation(SHG),dual-wavelength simultaneously tunable emission at the 1.1μm and 1.2μm bands for the sum-frequency generation(SFG),and dual-wavelength separation tunable emission for difference-frequency generation(DFG).As a result,with the combination of SHG and SFG in a periodically poled lithium niobate crystal array,we experimentally demonstrate the broadest tuning range(560-630 nm)of visible light generated from an RRFL,to the best of our knowledge.The tunable MIR light in the range of 10.7-12.3μm is also demonstrated through DFG of an RRFL operating in separation tunable dual-wavelength emission mode in a Ba Ga4Se7(BGSe)crystal,which is the first realization of>10μm CW DFG in the BGSe crystal.We believe the developed dual-wavelength switchable and tunable RRFL can provide a new compact,robust,and cost-effective platform to realize broadly tunable light in both the visible and MIR regions,which can also find potential applications in imaging,sensing,and temporal ghost imaging in various spectral bands.展开更多
Terahertz spectral responses have been studied for five borate crystals Na5[B2P3O13] (NBP), Zn3BPO (ZBP), SrB4O7 (SBO), Na3La9O3(BO 3)8 (NLBO) and PbB4O7 (PBO). It is found that the samples had good transmission in 0...Terahertz spectral responses have been studied for five borate crystals Na5[B2P3O13] (NBP), Zn3BPO (ZBP), SrB4O7 (SBO), Na3La9O3(BO 3)8 (NLBO) and PbB4O7 (PBO). It is found that the samples had good transmission in 0.25―1.5 THz region. Both SBO and NLBO have an absorption coefficient less than 10 cm1. Among them, SBO has not only the smallest absorption coefficient but also a very flat dispersion in the frequency region under investigation. Distinct resonance absorption peaks are observed for ZBP at ν1 = 1.4 THz, ν2 = 2.0 THz and SBO at ν = 2.4 THz. In the spectrum of PBO, two abnormal dispersions appear in the frequency regions 1.44―1.74 and 2.2―2.5 THz. The absorption coefficients and refraction indices of the five crystals are extracted from the THz time-domain (THz-TDS) spectra in 0.25―2.5 THz region. The properties and origins of the spectral responses are addressed.展开更多
We report an efficient mid-infrared extracavity optical parametric oscillator(OPO)based on the nonlinear crystal BaGa4Se7 pumped by a diode-side-pumped Q-switched Nd:Y3 Al5O12(Nd:YAG)laser.The maximum pulse energy of ...We report an efficient mid-infrared extracavity optical parametric oscillator(OPO)based on the nonlinear crystal BaGa4Se7 pumped by a diode-side-pumped Q-switched Nd:Y3 Al5O12(Nd:YAG)laser.The maximum pulse energy of 1.03mJ at 4.25μm is obtained with the repetition rate of 10 Hz and pulse width of 12.6 ns when the pump energy was 13.5mJ,corresponding to an optical-to-optical conversion efficiency of 7.6% from 1.064μm to 4.25μm.The idler wave slope conversion efficiency was 12%.To the best of our knowledge,it is the highest reported conversion efficiency for the compact BaGa4Se7 OPO driven by the Nd:YAG laser.展开更多
Design and exploratory synthesis of novel infrared nonlinear optical chalcogenides have drawn extensive concerns owing to their excellent overall performance and important role in laser industry.During the past decade...Design and exploratory synthesis of novel infrared nonlinear optical chalcogenides have drawn extensive concerns owing to their excellent overall performance and important role in laser industry.During the past decades,a large number of infrared nonlinear optical chalcogenides have been developed and many effective design strategies have been summarized,which illuminates the path of future explorations.In this perspective,we discuss the feasibility and effectiveness of the representative design ideas.Moreover,we point out some topics to be investigated and discuss the future research directions.展开更多
基金supported by the National Natural Science Foundation of China(No.50972149,61138004,51402316)the National Instrumentation Program(No.2012YQ120048)
文摘Two new isostructural multi-metal beryllium borates, m^3 Li Na4Be4B10O24F（M = Sr（1）, Cd（2））, have been synthesized by spontaneous crystallization. The structures were verified by single-crystal X-ray crystallography. The compounds crystallize in the trigonal space group R 3, with a = b = 9.4645（1） A, c = 38.842（8） A, V = 3013.2（6） A3, Z = 6, F（000） = 2568, Dc = 3.005 g/cm^3, Mr = 908.9, R = 0.0327, w R = 0.0678, μ = 8.160 mm-1 for Sr3 Li Na4Be4B10O24F and a = b = 9.3019（8） A, c = 37.782（7） A, V = 2831.12（9） A3, Z = 6, F（000） = 2748, Dc = 3.459 g/cm^3, Mr = 983.24, R = 0.0158, w R = 0.0455, μ = 3.586 mm-1 for Cd3 Li Na4Be4B10O24F. The structures are characterized by an infinite two-dimensional [Be8B16O40F2]∞ double layer bridged by [B12O24] groups like a sandwich structure, while the cations reside in tunnels along different directions. UV-vis-IR diffuse reflectance spectroscopy demonstrates that their cut-off edges are below 200 nm. Thermal analysis shows that they melt incongruently and their melting points are around 740-770 ℃.
基金supported by the National Natural Science Foundation of China (50590402 and 50802100)
文摘Pr3+ doped La2CaB10O19 crystal were grown by the top-seeded solution growth(TSSG) method.The absorption spectra,emission spectra and lifetime were measured at room temperature.The J-O parameters(Ωt,t=2,4,6),the radiative transition probabilities AJ,J ,oscillator strengths PJ,J ,radiative lifetime τ,fluorescence branch ratios βJ and the value of integrated emission cross section have also been calculated.Five main absorption bands,3H4 to 3P1+3P2,3P0,1D2,3F3 + 3F4 and 3F2,were observed in the absorption spect...
文摘Polycrystalline nano-sized neodymium doped yttrium aluminum garnet (Nd∶Y3Al5O12, Nd∶YAG) powders were synthesized via a gel combustion method using nitrates and citric acid as starting materials. The evolution of phase composition and micro-structure of the powders were characterized by X-ray powder diffraction, thermogravimetry/differential thermal analysis and scanning electron microscopy. Well-crystallized Nd∶YAG nano-sized powders could be obtained at 950 ℃ for 2 h. The resultant powders are well dispersed, have a relatively narrow size distribution with an average particle size of approximately 50 nm, and show excellent sinterability. These powders can be densified to 99.2% of the theoretical density by HP sintering at 1700 ℃ for 3 h under 20 MPa nitrogen pressure.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11274367,10904097,and 11274233) and Chinese Academy of Sciences
文摘LaOsSi3 single crystals are synthesized for the first time by an arc melting method. The crystal features a tetrag- onal BaNiSn3-type structure （space group 14mm） which lacks inversion symmetry along the crystallographic c axis and is isostructural with the intensively studied Rashba-type noncentrosymmetric superconductors LaRhSi3 and LaIrSi3. Un- like LaRhSi3 and LaIrSi3 displaying superconductivity, LaOsSi3 shows only metallic behavior over the measured temper- ature range of 2 K-300 K. The Sommerfeld coefficient ]/derived from specific heat is 5.76 mJ.mol-1 -K-2, indicating that LaOsSi3 has a weak electronic correlation effect. The absence of superconductivity in LaOsSi3 may lie in the Os 5d bands in the electronic structure. If it is true, it would be useful to provide complementary knowledge in understanding the relation between conduction and the d bands of M in LaMSi3 compounds （M = transition metals）.
文摘A special prism coupling technique with the KBe_(2)BO_(3)F_(2) crystal is adopted to produce deep ultraviolet light including the fourth harmonic from an Nd:YAG laser,for which a conversion efficiency as high as 10%has been obtained.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50972149 and 61138004the National High Technology Research and Development Program of China under Grant No 2011AA030202.
文摘High-average-power fourth-harmonic generation (4thHG) of an Nd:YAG laser is achieved with a RbBe_(2)BO_(3)F_(2) (RBBF) costal.A maximum output power of 3 W at 266nm is obtained.To our knowledge,this is the first time that efficient 4th HG is realized with RBBF.The angular bandwidth of 4th HG is also measured.
基金This work was supported by the Chinese Academy of Sciences (2004AA31g130)
文摘Single crystals of LiY6O5（BO3）3 were obtained by the flux method and its structure was determined by a four-circle automatic diffractometer with a MoKα radiation. It crystallizes in monoclinic, space group P21/n with a = 8.330（3）, b = 15.444（4）, c = 8.780（3）°A,β = 91.85（3）°, V = 1129.0（6）°A^3, Z = 4, Mr= 796.83, F（000） = 1456, μ = 30.567 mm^-1, Dc= 4.688 g/cm^3, the final R = 0.0722 and wR = 0.1304. It exhibits a three-dimensional fiamework of yttrium-oxygen polyhedra interconnected by common edges and corners. B and Li atoms are located in the planes and cavities formed by oxygen atoms, respectively.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52301241 and 52271175)。
文摘The barocaloric effect is considered as one of the most promising refrigeration with the potential to replace traditional gas compression refrigeration.One of the main obstacles to the application of barocaloric materials lies in the requirement for high driving pressures.In this paper,we report on the barocaloric effect of Pb_(3)(VO_(4))_(2),which exhibits a ferroelastic transition from a high-temperature trigonal structure to a low-temperature monoclinic structure at 357 K,accompanied by a substantial volume change.The entropy change induced by hydrostatic pressure can reach up 14 J·kg^(-1)·K^(-1)under a relatively low pressure of 80 MPa.This work is expected to expand the selection range of barocaloric materials.
文摘Tetraethylenepentamine(C8H23N5,TEPA) has been used as a novel precipitant to synthesize yttrium aluminum garnet(Y3Al5O12,YAG) precursor from a mixed solution of aluminum and yttrium nitrates via a normal-strike co-precipitation method without controlling the pH value during precipitation process.The original precursor was analyzed by thermogravimetry/differential scanning calorimetry(TG/DSC).The evolution of phase composition and micro-structure of the as-synthesized YAG powders were characterized by X-ray ...
基金supported by the National Key Research and Development Program of China(2021 YFB3601502)the National Natural Science Foundation of China(52172011).
文摘1.Introduction Inorganic borate crystals have received considerable attention in many applications as nonlinear optical(NLO)crystals,birefringence crystals and scintillator materials[1-3].Recently,it is a well-known strategy for designing new NLO materials by utilizing NLO-active units.
基金Project supported by the National Key Research and Development Program of China(2022YFB3505102)the National Science Foundation for Excellent Young Scholars(52222107)+1 种基金the National Science Foundation for Distinguished Young Scholars(51925605)the National Natural Science Foundation of China(52171195)。
文摘We synthesized a potassium gadolinium phosphate K3Gd(PO_(4))_(2)with monoclinic structure(P2_(1/m))by the high-temperature solid-state reaction method.Its lattice constants obtained by Rietveld refinements of XRD curve are a=0.7411 nm,b=0.5624 nm,and c=0.9433 nm.Magnetic and magnetocaloric properties of K_(3)Gd(PO_(4))_(2)were investigated in detail.The magnetic phase transition temperature of K3Gd(PO_(4))2 was determined by ultra-low temperature testing to be 0.58 K.K_(3)Gd(PO_(4))2 exhibits large magnetic entropy changes(-ΔSM).The maximum-ΔSM are 20.2 and 29.4 J/(kg·K)in the magnetic field variation(ΔH)of 1 and 2 T,respectively,which are larger than that of the commercial Gd_(3)Ga_(5)O_(12)(GGG).The maximum adiabatic temperature change(ΔT_(ad))reaches 5.91 K under a magnetic field change(ΔH)of 1 T.K_(3)Gd(PO_(4))_(2)is a potential magnetic refrigeration material for obtaining sub-Kelvin temperatures.
基金National Natural Science Foundation of China(62005186,62075144,61875132)Engineering Featured Team Fund of Sichuan University(2020SCUNG105)Fundamental Research Funds for the Central Universities(YJ201979,YJ201982)。
文摘Nonlinear frequency conversion of wavelength agile and high-power random fiber lasers can provide a promising way to generate continuous-wave(CW)visible and mid-infrared(MIR)light with unique properties such as the continuous modeless spectrum,low temporal/spatial coherence,and high temporal stability.Here,we report a dual-wavelength switchable and tunable random Raman fiber laser(RRFL)based on a phosphosilicate fiber that has two Raman gain peaks for the first time and demonstrate its superior capability to generate widely tunable CW visible and mid-infrared light via nonlinear frequency conversions.By using the combination of a tunable pump and two tunable gratings in Littrow configuration that can provide separated point feedback for the two Stokes wavelengths corresponding to silica-and phosphorus-related Raman peaks,the spectrum of an RRFL can be flexibly manipulated for the aim of nonlinear frequency conversions,including single-wavelength tunable emission at the 1.1μm or 1.2μm band for second-harmonic generation(SHG),dual-wavelength simultaneously tunable emission at the 1.1μm and 1.2μm bands for the sum-frequency generation(SFG),and dual-wavelength separation tunable emission for difference-frequency generation(DFG).As a result,with the combination of SHG and SFG in a periodically poled lithium niobate crystal array,we experimentally demonstrate the broadest tuning range(560-630 nm)of visible light generated from an RRFL,to the best of our knowledge.The tunable MIR light in the range of 10.7-12.3μm is also demonstrated through DFG of an RRFL operating in separation tunable dual-wavelength emission mode in a Ba Ga4Se7(BGSe)crystal,which is the first realization of>10μm CW DFG in the BGSe crystal.We believe the developed dual-wavelength switchable and tunable RRFL can provide a new compact,robust,and cost-effective platform to realize broadly tunable light in both the visible and MIR regions,which can also find potential applications in imaging,sensing,and temporal ghost imaging in various spectral bands.
基金the National Natural Science Foundation of China (Grant Nos. 50672104 and 10390160)
文摘Terahertz spectral responses have been studied for five borate crystals Na5[B2P3O13] (NBP), Zn3BPO (ZBP), SrB4O7 (SBO), Na3La9O3(BO 3)8 (NLBO) and PbB4O7 (PBO). It is found that the samples had good transmission in 0.25―1.5 THz region. Both SBO and NLBO have an absorption coefficient less than 10 cm1. Among them, SBO has not only the smallest absorption coefficient but also a very flat dispersion in the frequency region under investigation. Distinct resonance absorption peaks are observed for ZBP at ν1 = 1.4 THz, ν2 = 2.0 THz and SBO at ν = 2.4 THz. In the spectrum of PBO, two abnormal dispersions appear in the frequency regions 1.44―1.74 and 2.2―2.5 THz. The absorption coefficients and refraction indices of the five crystals are extracted from the THz time-domain (THz-TDS) spectra in 0.25―2.5 THz region. The properties and origins of the spectral responses are addressed.
基金supported by the Science and Technology on Plasma Physics Laboratory(No.6142A04030403)the Innovation Fund of the Chinese Academy of Sciences(No.CXJJ-17-M164)
文摘We report an efficient mid-infrared extracavity optical parametric oscillator(OPO)based on the nonlinear crystal BaGa4Se7 pumped by a diode-side-pumped Q-switched Nd:Y3 Al5O12(Nd:YAG)laser.The maximum pulse energy of 1.03mJ at 4.25μm is obtained with the repetition rate of 10 Hz and pulse width of 12.6 ns when the pump energy was 13.5mJ,corresponding to an optical-to-optical conversion efficiency of 7.6% from 1.064μm to 4.25μm.The idler wave slope conversion efficiency was 12%.To the best of our knowledge,it is the highest reported conversion efficiency for the compact BaGa4Se7 OPO driven by the Nd:YAG laser.
基金supported by the National Natural Science Foundation of China(Nos.51890862 and 61675212)。
文摘Design and exploratory synthesis of novel infrared nonlinear optical chalcogenides have drawn extensive concerns owing to their excellent overall performance and important role in laser industry.During the past decades,a large number of infrared nonlinear optical chalcogenides have been developed and many effective design strategies have been summarized,which illuminates the path of future explorations.In this perspective,we discuss the feasibility and effectiveness of the representative design ideas.Moreover,we point out some topics to be investigated and discuss the future research directions.
