Exploring new material systems and enhancing the birefringence of compounds is a highly valuable endeavor.In this study,we introduce a novel method to enhance the birefringence of inorganic compounds by inducing struc...Exploring new material systems and enhancing the birefringence of compounds is a highly valuable endeavor.In this study,we introduce a novel method to enhance the birefringence of inorganic compounds by inducing structural alignment through linear groups and fluoride ions.We report on two new compounds:HgGa2(SeO3)4 and Hg2Ga(SeO3)2F.HgGa2(SeO3)4 crystallizes in a non-centrosymmetric(NCS)space group,exhibiting a second harmonic generation(SHG)efficiency of approximately 60% that of commercial KH2PO4(KDP),with a birefringence of 0.032@546 nm.Hg2Ga(SeO3)2F,on the other hand,crystallizes in a centrosymmetric space(CS)group and represents the first reported HgI-based selenite birefringent material.Due to the influence of the linear group Hg2O2,its birefringence is significantly enhanced to 0.111@546 nm,which is 3.5 times that of HgGa2(SeO3)4.Moreover,both compounds demonstrate high stability and a broad optical transparency window.These findings indicate that Hg2Ga(SeO3)2F is a promising candidate for birefringent material in the mid-infrared(MIR)range.Our research provides an innovative strategy for improving the birefringence of compounds.展开更多
Ultraviolet(UV)nonlinear optical(NLO)crystals have received substantial interest in advanced laser technology.However,tailoring a UV NLO material with a large second harmonic generation(SHG)response and good UV transp...Ultraviolet(UV)nonlinear optical(NLO)crystals have received substantial interest in advanced laser technology.However,tailoring a UV NLO material with a large second harmonic generation(SHG)response and good UV transparency remains a challenge.Here,inspired by the classic A3-RE2-[BO3]3 parent template,two new rare-earth borate NLO crystals,RbNa2La2(BO3)3(RNLBO-Ⅰ)and Rb0.681Na2.319La2(BO3)3(RNLBO-Ⅱ),were extracted by merging larger ionic radius cations Rb+and La3+simultaneously using a chemical substitution-oriented strategy.As expected,both compounds achieve significant enhancements in SHG activities,reaching 4.5×and 4.3×KDP,respectively,exceeding three times that of the isomorphic Na3Gd2B3O9.Notably,RNLBO-Ⅰdisplayed the highest SHG response among alkali metal RE-borate NLO crystals containing isolated[BO3]groups in the short-wave UV region.Moreover,RNLBO-Ⅰand-Ⅱdemonstrated short UV cutoff edges at 213 and 207 nm,corresponding to wide bandgaps of 5.3 and 5.6 eV,respectively.Additionally,theoretical calculations and dipole moment analysis were conducted to clarify the origin of the enhanced SHG activities of RNLBO-Ⅰand-Ⅱ.The optimal balance between SHG intensity and UV transparency in RNLBO-Ⅰand-Ⅱunderscores their potential as UV NLO candidates and offers valuable insights for fabricating new advanced UV NLO materials.展开更多
为了解决连续谱中束缚态空间响应带宽偏小的技术难题,本文设计了一种简单的光子晶体平板,并进行能带的计算和模式Q因子分析.通过结构参数的优化,在k空间发现一种正方形环状的且边长可调节的准连续谱中束缚态(bound state in the continu...为了解决连续谱中束缚态空间响应带宽偏小的技术难题,本文设计了一种简单的光子晶体平板,并进行能带的计算和模式Q因子分析.通过结构参数的优化,在k空间发现一种正方形环状的且边长可调节的准连续谱中束缚态(bound state in the continuum, BIC)分布.分析准BIC环与等频线的关系以及模场分布的特征发现,这种正方形环状的准BIC来自结构的全内反射和驻波干涉效应.分别通过入射角度和频率扫描计算结构的透射谱,得到了高Q因子的法诺共振谱线,进而验证了环状准BIC的存在.展开更多
Nd,Y:CaF2(NYCF)crystals are exceptional gain materials for high-power laser drivers;however,laser-induced damage remains a substantial challenge that restricts their broader application.In this study,by establishing a...Nd,Y:CaF2(NYCF)crystals are exceptional gain materials for high-power laser drivers;however,laser-induced damage remains a substantial challenge that restricts their broader application.In this study,by establishing an in situ testing system for photothermal weak absorption and the laser-induced damage threshold(LIDT),the relationship between the photothermal weak absorption characteristics of NYCF and its LIDTs was analyzed.A fully connected neural network was employed to facilitate deep learning of these relationships,thereby enabling non-destructive evaluation of NYCF via photothermal weak absorption.Moreover,this study examined both the effect of spot size during testing and the influence of crystal orientation on the evaluation outcomes.The underlying mechanisms were further elucidated by investigating NYCF's thermal mechanical properties and damage characteristics.This work not only offers a rapid,nondestructive method for evaluating the laser damage resistance of NYCF using artificial intelligence but also enhances the understanding of its damage mechanisms.展开更多
Precise control over the angular response of light is essential for advanced photonic devices.Here,we develop a constitutive-parameters-based framework for customizable angular selection.We introduce a pseudo-local ef...Precise control over the angular response of light is essential for advanced photonic devices.Here,we develop a constitutive-parameters-based framework for customizable angular selection.We introduce a pseudo-local effective medium theory,leveraging Brillouin zone folding in photonic crystal supercells,to effectively realize the required parameters for a designated incident crystal face.At the operating frequency,simulations and microwave experiments demonstrate that the designed photonic crystal achieves sharp angular selection from near-total transmission(97%)to near-perfect reflection within an angular transition bandwidth of~3°.Additionally,by integrating a hyperbolic medium with an anisotropic medium,we realize in simulation an angular bandpass filter centered at 30°with a near 1°full width at half-maximum.This work provides a quantitative design methodology for angular-selective photonic crystals and metamaterials,paving the way for applications such as antenna sidelobe suppression,solar energy harvesting,and privacy displays.展开更多
LiGaS2 crystals are prospective media for optical parametric oscillators. In such systems efficiency and maximum power output are often limited by the laser-induced damage threshold(LIDT) of nonlinear crystals. In add...LiGaS2 crystals are prospective media for optical parametric oscillators. In such systems efficiency and maximum power output are often limited by the laser-induced damage threshold(LIDT) of nonlinear crystals. In addition, most nonlinear crystals have a high refractive index and consequently large Fresnel losses, thus encouraging the use of antireflection coatings. However, antireflection coatings are known to compromise the LIDT. This work presents results of the LIDT testing of LiGaS2 nonlinear crystals in untreated, antireflection-coated and antireflection-microstructured variations.The tests were performed using a one-on-one method with pulsed lasers operating at 1.57, 2.09 and 2.5 μm wavelengths with pulse durations of 9, 149 and 12 ns, respectively. The paper covers damage site feature investigation and LIDT comparison of antireflection coating and antireflection microstructures. The key finding of the work is that antireflection microstructures can provide an increase in transmittance for both the pump and the signal, while maintaining a high LIDT.展开更多
Nonlinear optical(NLO)crystals with efficient frequency conversion are essential for all-solid-state lasers,and exploring new second harmonic generation(SHG)enhancing strategy is crucial for the structure-property rel...Nonlinear optical(NLO)crystals with efficient frequency conversion are essential for all-solid-state lasers,and exploring new second harmonic generation(SHG)enhancing strategy is crucial for the structure-property rela-tionship research and application of NLO crystals.Conventional strategies focus on inducing parallel alignment of NLO active units.In this work,two new regulation means,i.e.bond polarization and flexible deformation,have been identified in rare earth carbonates REXCO3(RE=La,Ce,Y;X=OH,F)with anionic motifs circular aligned through experimental characterization and first-principles calculations.They can promote the SHG effect in the form of electronic polarization and polyhedra distortion,respectively.Such regulation methods break the common acceptation that only carbonates aligning in a parallel pattern can effectively achieve the superposition of hyperpolarizabilities and result in considerable SHG effect.By realizing the synergistic effect of circular alignment and rare earth polyhedra,the polarizability and flexible stretching ability of the RE-O coordination bonds are effectively exerted in the designed structure,C2_La2O2CO3.This work unveils a new mechanism for SHG enhancement in rare earth carbonates and provides new insight for designing advanced NLO materials.展开更多
Achieving non-centrosymmetric(NCS) configurations in ABX3-type hybrid halides remains a critical challenge for nonlinear optical(NLO) materials due to the conflicting requirements of high second-harmonic generation(SH...Achieving non-centrosymmetric(NCS) configurations in ABX3-type hybrid halides remains a critical challenge for nonlinear optical(NLO) materials due to the conflicting requirements of high second-harmonic generation(SHG) response,wide bandgap,and phase-matching capabilities.Herein,we propose a triplesite modulation strategy by synergistically tailoring the A-site cations(2-methylimidazole cation/1-ethyl-3-methylimidazole cation),B-site metals(Sn2+/Pb2+),and X-site halogens(Cl/Br),which effectively disrupts lattice symmetry and enables NCS crystallization.Our results demonstrate a strong SHG response,an expanded optical bandgap and increased birefringence.The optimized compound C6H11N2PbCl3 exhibits a moderately strong SHG efficiency of 3.8 × KDP,a wide bandgap(3.87 eV),and enhanced birefringence(0.139@1064 nm),surpassing majority hybrid NLO materials.The innovative anionic framework introduced here broadens the scope of hybrid NLO crystals,facilitating the integration of various aromatic heterocyclic cations.This research provides a robust strategic framework for the development of advanced NLO materials.展开更多
In photonic systems,the synthetic pseudo-magnetic field can influence electrically neutral photons in a manner analogous to real magnetic fields on electrons,thereby offering an approach for light manipulation.Here,we...In photonic systems,the synthetic pseudo-magnetic field can influence electrically neutral photons in a manner analogous to real magnetic fields on electrons,thereby offering an approach for light manipulation.Here,we construct two-dimensional photonic crystals composed of all-dielectric materials,where engineering rotation angles result in spatially varying gradients of opened Dirac cones corresponding to position-dependent mass terms.The induced in-plane pseudo-magnetic field gives rise to chiral zeroth-order Landau levels.We design and experimentally demonstrate photonic Dirac cavities based on the bulk state propagation of chiral Landau levels,exhibiting large-area Dirac mode distributions.The proposed photonic cavities demonstrate a significant capability to control confinement strength and spatial distribution of the trapped Dirac modes induced by the variation of the mass term.These findings represent an important step toward utilizing Dirac cavities for light confinement in integrated photonics and enhancing light–matter interactions,thereby contributing substantially to various device applications.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22475215,22031009 and 21921001)the NSF of Fujian Province(Nos.2023J01216,2024J010039)the Selfdeployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences(No.CXZX-2022-GH06).
摘要Exploring new material systems and enhancing the birefringence of compounds is a highly valuable endeavor.In this study,we introduce a novel method to enhance the birefringence of inorganic compounds by inducing structural alignment through linear groups and fluoride ions.We report on two new compounds:HgGa2(SeO3)4 and Hg2Ga(SeO3)2F.HgGa2(SeO3)4 crystallizes in a non-centrosymmetric(NCS)space group,exhibiting a second harmonic generation(SHG)efficiency of approximately 60% that of commercial KH2PO4(KDP),with a birefringence of 0.032@546 nm.Hg2Ga(SeO3)2F,on the other hand,crystallizes in a centrosymmetric space(CS)group and represents the first reported HgI-based selenite birefringent material.Due to the influence of the linear group Hg2O2,its birefringence is significantly enhanced to 0.111@546 nm,which is 3.5 times that of HgGa2(SeO3)4.Moreover,both compounds demonstrate high stability and a broad optical transparency window.These findings indicate that Hg2Ga(SeO3)2F is a promising candidate for birefringent material in the mid-infrared(MIR)range.Our research provides an innovative strategy for improving the birefringence of compounds.
基金supported by the National Key R&D Program of China(No.2021YFA0717800)National Natural Science Foundation of China(Nos.62475191,61835014,and 52327801).
摘要Ultraviolet(UV)nonlinear optical(NLO)crystals have received substantial interest in advanced laser technology.However,tailoring a UV NLO material with a large second harmonic generation(SHG)response and good UV transparency remains a challenge.Here,inspired by the classic A3-RE2-[BO3]3 parent template,two new rare-earth borate NLO crystals,RbNa2La2(BO3)3(RNLBO-Ⅰ)and Rb0.681Na2.319La2(BO3)3(RNLBO-Ⅱ),were extracted by merging larger ionic radius cations Rb+and La3+simultaneously using a chemical substitution-oriented strategy.As expected,both compounds achieve significant enhancements in SHG activities,reaching 4.5×and 4.3×KDP,respectively,exceeding three times that of the isomorphic Na3Gd2B3O9.Notably,RNLBO-Ⅰdisplayed the highest SHG response among alkali metal RE-borate NLO crystals containing isolated[BO3]groups in the short-wave UV region.Moreover,RNLBO-Ⅰand-Ⅱdemonstrated short UV cutoff edges at 213 and 207 nm,corresponding to wide bandgaps of 5.3 and 5.6 eV,respectively.Additionally,theoretical calculations and dipole moment analysis were conducted to clarify the origin of the enhanced SHG activities of RNLBO-Ⅰand-Ⅱ.The optimal balance between SHG intensity and UV transparency in RNLBO-Ⅰand-Ⅱunderscores their potential as UV NLO candidates and offers valuable insights for fabricating new advanced UV NLO materials.
摘要为了解决连续谱中束缚态空间响应带宽偏小的技术难题,本文设计了一种简单的光子晶体平板,并进行能带的计算和模式Q因子分析.通过结构参数的优化,在k空间发现一种正方形环状的且边长可调节的准连续谱中束缚态(bound state in the continuum, BIC)分布.分析准BIC环与等频线的关系以及模场分布的特征发现,这种正方形环状的准BIC来自结构的全内反射和驻波干涉效应.分别通过入射角度和频率扫描计算结构的透射谱,得到了高Q因子的法诺共振谱线,进而验证了环状准BIC的存在.
基金supported by the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-024)the National Natural Science Foundation of China(Grant Nos.62505338 and W2412088)。
摘要Nd,Y:CaF2(NYCF)crystals are exceptional gain materials for high-power laser drivers;however,laser-induced damage remains a substantial challenge that restricts their broader application.In this study,by establishing an in situ testing system for photothermal weak absorption and the laser-induced damage threshold(LIDT),the relationship between the photothermal weak absorption characteristics of NYCF and its LIDTs was analyzed.A fully connected neural network was employed to facilitate deep learning of these relationships,thereby enabling non-destructive evaluation of NYCF via photothermal weak absorption.Moreover,this study examined both the effect of spot size during testing and the influence of crystal orientation on the evaluation outcomes.The underlying mechanisms were further elucidated by investigating NYCF's thermal mechanical properties and damage characteristics.This work not only offers a rapid,nondestructive method for evaluating the laser damage resistance of NYCF using artificial intelligence but also enhances the understanding of its damage mechanisms.
基金National Key Research and Development Program of China(2020YFA0211300)National Natural Science Foundation of China(12474293,12174188)+1 种基金Natural Science Foundation of Jiangsu Province(BK20233001)Postdoctoral Fellowship Program of CPSF(GZC20252238)。
摘要Precise control over the angular response of light is essential for advanced photonic devices.Here,we develop a constitutive-parameters-based framework for customizable angular selection.We introduce a pseudo-local effective medium theory,leveraging Brillouin zone folding in photonic crystal supercells,to effectively realize the required parameters for a designated incident crystal face.At the operating frequency,simulations and microwave experiments demonstrate that the designed photonic crystal achieves sharp angular selection from near-total transmission(97%)to near-perfect reflection within an angular transition bandwidth of~3°.Additionally,by integrating a hyperbolic medium with an anisotropic medium,we realize in simulation an angular bandpass filter centered at 30°with a near 1°full width at half-maximum.This work provides a quantitative design methodology for angular-selective photonic crystals and metamaterials,paving the way for applications such as antenna sidelobe suppression,solar energy harvesting,and privacy displays.
基金the Russian Science Foundation(project 20-72-10027-P) for the support of crystal growth,ARM fabrication and LIDT measurementsthe state assignment of the V.S. Sobolev Institute of Geology and Mineralogy SB RAS (122041400031-2) for the support of charge composition analysis for the crystal synthesis。
摘要LiGaS2 crystals are prospective media for optical parametric oscillators. In such systems efficiency and maximum power output are often limited by the laser-induced damage threshold(LIDT) of nonlinear crystals. In addition, most nonlinear crystals have a high refractive index and consequently large Fresnel losses, thus encouraging the use of antireflection coatings. However, antireflection coatings are known to compromise the LIDT. This work presents results of the LIDT testing of LiGaS2 nonlinear crystals in untreated, antireflection-coated and antireflection-microstructured variations.The tests were performed using a one-on-one method with pulsed lasers operating at 1.57, 2.09 and 2.5 μm wavelengths with pulse durations of 9, 149 and 12 ns, respectively. The paper covers damage site feature investigation and LIDT comparison of antireflection coating and antireflection microstructures. The key finding of the work is that antireflection microstructures can provide an increase in transmittance for both the pump and the signal, while maintaining a high LIDT.
基金financially supported by the National Natural Science Foundation of China(Nos.12174404 and 22275201).
摘要Nonlinear optical(NLO)crystals with efficient frequency conversion are essential for all-solid-state lasers,and exploring new second harmonic generation(SHG)enhancing strategy is crucial for the structure-property rela-tionship research and application of NLO crystals.Conventional strategies focus on inducing parallel alignment of NLO active units.In this work,two new regulation means,i.e.bond polarization and flexible deformation,have been identified in rare earth carbonates REXCO3(RE=La,Ce,Y;X=OH,F)with anionic motifs circular aligned through experimental characterization and first-principles calculations.They can promote the SHG effect in the form of electronic polarization and polyhedra distortion,respectively.Such regulation methods break the common acceptation that only carbonates aligning in a parallel pattern can effectively achieve the superposition of hyperpolarizabilities and result in considerable SHG effect.By realizing the synergistic effect of circular alignment and rare earth polyhedra,the polarizability and flexible stretching ability of the RE-O coordination bonds are effectively exerted in the designed structure,C2_La2O2CO3.This work unveils a new mechanism for SHG enhancement in rare earth carbonates and provides new insight for designing advanced NLO materials.
基金supported by the National Natural Science Foundation of China (No.22275052)Department of Science and Technology of Hubei Province (Nos.2025AFA111 and 2024CSA076)。
摘要Achieving non-centrosymmetric(NCS) configurations in ABX3-type hybrid halides remains a critical challenge for nonlinear optical(NLO) materials due to the conflicting requirements of high second-harmonic generation(SHG) response,wide bandgap,and phase-matching capabilities.Herein,we propose a triplesite modulation strategy by synergistically tailoring the A-site cations(2-methylimidazole cation/1-ethyl-3-methylimidazole cation),B-site metals(Sn2+/Pb2+),and X-site halogens(Cl/Br),which effectively disrupts lattice symmetry and enables NCS crystallization.Our results demonstrate a strong SHG response,an expanded optical bandgap and increased birefringence.The optimized compound C6H11N2PbCl3 exhibits a moderately strong SHG efficiency of 3.8 × KDP,a wide bandgap(3.87 eV),and enhanced birefringence(0.139@1064 nm),surpassing majority hybrid NLO materials.The innovative anionic framework introduced here broadens the scope of hybrid NLO crystals,facilitating the integration of various aromatic heterocyclic cations.This research provides a robust strategic framework for the development of advanced NLO materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.12574477,52227901,and 12274315)the Fundamental Research Funds for the Central Universities(Grant No.2023ZDYQ11003).
摘要In photonic systems,the synthetic pseudo-magnetic field can influence electrically neutral photons in a manner analogous to real magnetic fields on electrons,thereby offering an approach for light manipulation.Here,we construct two-dimensional photonic crystals composed of all-dielectric materials,where engineering rotation angles result in spatially varying gradients of opened Dirac cones corresponding to position-dependent mass terms.The induced in-plane pseudo-magnetic field gives rise to chiral zeroth-order Landau levels.We design and experimentally demonstrate photonic Dirac cavities based on the bulk state propagation of chiral Landau levels,exhibiting large-area Dirac mode distributions.The proposed photonic cavities demonstrate a significant capability to control confinement strength and spatial distribution of the trapped Dirac modes induced by the variation of the mass term.These findings represent an important step toward utilizing Dirac cavities for light confinement in integrated photonics and enhancing light–matter interactions,thereby contributing substantially to various device applications.