Erosion test of some infrared （IR） optical crystals （Ge, ZnS, MgF2, and quartz） was conducted with a number of different erodents （glass bead, and angular SiC, SiO2, Al2O3） by a homemade gas-blasting erosion tes...Erosion test of some infrared （IR） optical crystals （Ge, ZnS, MgF2, and quartz） was conducted with a number of different erodents （glass bead, and angular SiC, SiO2, Al2O3） by a homemade gas-blasting erosion tester. The influence of impact angle, impact velocity, erodent, and erosion time on the erosion rate and the effect of erosion on their IR transmittance were studied. The dam- aged surface morphology was characterized by scanning electron microscopy, and the erosion mechanism was explored. All of the materials show the maximum in wear versus impact angle at 90°, confirming their brittle failure behavior. It is found that the erosion rate is dependent on the erodent velocity by a power law, and it is highly correlated to the hardness of the erodent. The erosion rate-time curves do not show an incubation state, but an accelerated erosion period followed a maximum erosion （steady state）. The decrease of IR transmittance is direct proportion to the erosion rate. Although the material loss occurs primarily by brittle process, ductile behavior is clearly an important feature, especially for MgF2 and ZnS.展开更多
We investigated image processing algorithms of the original infrared glass flaw image. Using the Laplacian edge enhancement following LSD （Line Segment Detector） algorithm, we can get a good flaw image very consiste...We investigated image processing algorithms of the original infrared glass flaw image. Using the Laplacian edge enhancement following LSD （Line Segment Detector） algorithm, we can get a good flaw image very consistent with the original one. This study is very helpful to further enhance the infrared glass flaw inspection technique.展开更多
Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target produc...Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target products were characterized by thermogravimetric analyzer,X-ray diffrotometer,fourier transform infrared spectrometer,scanning electron microscope,spectrophotometer and infrared emissivity tester,and the effects of Er^(3+)doping on its infrared and laser emissivity were studied.At the same time,the Sn_(1−x)Er_(x)O_(2)(x=0%,16%)doping models were constructed based on the first principles of density functional theory,and the related optoelectronic properties such as their energy band structure,density of states,reflectivity and dielectric constant were analyzed,and further explained the mechanism of Er^(3+)doping on SnO_(2)infrared emissivity and laser absorption from the point of electronic structure.The results showed that after calcination at 600℃,single rutile type SnO_(2)was formed,and the crystal structure was not changed by doping Er^(3+).The calcined products showed good fiber morphology,and the average fiber diameter was 402 nm.The infrared emissivity and resistivity of the samples both decreased first and then increased with the increase of Er^(3+)doping amount.When x=16%,the infrared emis-sivity of the sample was at least 0.71;and Er^(3+)doping can effectively reduce the reflectivity of SnO_(2)at 1.06μm and 1.55μm,when x=16%,its reflectivity at 1.06μm and 1.55μm are 50.5%and 40%,respectively,when x=24%,the reflectivity at 1.06μm and 1.55μm wavelengths are 47.3%and 42.1%,respectively.At the same time,the change of carrier concentration and electron transition before and after Er^(3+)doping were described by first-principle calculation,and the regulation mechanism of infrared emissivity and laser reflectivity was explained.This study provides a certain experimental and theoretical basis for the development of a single-type,light-weight and easily prepared infrared and laser compatible-stealth material.展开更多
Artificial adaptive soft infrared(IR)materials,mimicking the color-changing abilities observed in soft organisms such as cephalopods,hold significant promise in various emerging technologies,including unconventional f...Artificial adaptive soft infrared(IR)materials,mimicking the color-changing abilities observed in soft organisms such as cephalopods,hold significant promise in various emerging technologies,including unconventional flexible displays,intelligent camouflage systems,and advanced sensors.In this study,we integrated inherently deformable liquid metal(LM)microdroplets randomly into an elastomer matrix,creating a fully soft material that exhibits elastic compliance akin to soft biological tissue and adaptive IR-reflecting properties in response to compression.Under compressive strains,each LM inclusion behaves as a unit of dynamic IR reflector,transitioning between a contracted droplet with a corrugated surface and an expanded plate-like filler with a relatively smooth surface.These alterations in shape,size,and surface structure allow dynamic modulation of incident IR radiation's reflection,resulting in reversible changes in IR color(i.e.,detected temperature).This mechanism replicates the dynamic alterations observed in cephalopod skin,where chromatophores dynamically manipulate visible light reflection by changing their size and morphology.We demonstrate proof-of-concept applications of this material,showing its ability to modify IR appearance through compression for visualization,with its localized color-change mechanism enabling its use as a tactile sensor in vision-based tactile grippers.These illustrate the potential of this material in emerging adaptive flexible electronics.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
The infrared conformal window is one of the most critical components in aircraft.Conformal windows with high performance bring low aberrations,high aerodynamic performance,reliability in extreme working environments,a...The infrared conformal window is one of the most critical components in aircraft.Conformal windows with high performance bring low aberrations,high aerodynamic performance,reliability in extreme working environments,and added value for aircraft.Through the past decades,remarkable advances have been achieved in manufacturing technologies for conformal windows,where the machining accuracy approaches the nanometer level,and the surface form becomes more complex.These advances are critical to aircraft development,and these manufacturing technologies also have significant reference values for other directions of the ultra-precision machining field.In this review,the infrared materials suitable for manufacturing conformal windows are introduced and compared with insights into their performances.The remarkable advances and concrete work accomplished by researchers are reviewed.The challenges in manufacturing conformal windows that should be faced in the future are discussed.展开更多
As the core device of all-solid-state laser,infrared(IR)nonlinear optical(NLO)material plays a critical role in exploring new coherent lights by frequency conversion technologies,which are widely used in noninvasive m...As the core device of all-solid-state laser,infrared(IR)nonlinear optical(NLO)material plays a critical role in exploring new coherent lights by frequency conversion technologies,which are widely used in noninvasive medical diagnostics,spectroscopy,environmental monitoring and long-distance laser communication.To satisfy the growing demand of current laser technology in IR regions,high performance NLO materials with large second-harmonic generation(SHG)response,high laser-induced damage threshold(LIDT)and wide transparency range are highly expected.Recently,numerous efforts and advances have been achieved in sulfide system.This review highlights the progress of high-performance sulfide IR NLO materials with a good balance between strong SHG response(≥1.0×AgGaS_(2))and wide band gap(≥3.0 eV)since 2018.The chemical synthesis,crystal structure,optical properties and structure-property relationship of 13 high performance metal sulfide IR NLO materials are summarized and reviewed in detail.Finally,the potential opportunities and challenges in IR NLO materials are discussed.展开更多
Hypersonic vehicles subjected to strong aerodynamic forces and serious aerodynamic heating require more stringent design for an infrared window. In this paper, a finite element analysis is used to present the distribu...Hypersonic vehicles subjected to strong aerodynamic forces and serious aerodynamic heating require more stringent design for an infrared window. In this paper, a finite element analysis is used to present the distributions of thermal and stress fields in the infrared window for hypersonic vehicles based on flowfield studies. A theoretical guidance is provided to evaluate the influence of aerodynamic heating and forces on infrared window materials. The aerodynamic heat flux from Mach 3 to Mach 6 flight at an altitude of 15 km in a standard atmosphere is obtained through flowfield analysis. The thermal and stress responses are then investigated under constant heat transfer coefficient boundary conditions for different Mach numbers. The numerical results show that the maximum stress is higher than the material strength at Mach 6, which means a failure of the material may occur. The maximum stress and temperatures are lower than the material strength and melting point under other conditions, so the material is safe.展开更多
ZnS-Diatnond cotnPOsites (ZnS/D) were fabricated by hot pressing to obtain a ZnS ithered transparent materials with incmeed toughness. The relations of the mechanical properties and the diomond contents were investiga...ZnS-Diatnond cotnPOsites (ZnS/D) were fabricated by hot pressing to obtain a ZnS ithered transparent materials with incmeed toughness. The relations of the mechanical properties and the diomond contents were investigated. It was determined that,when the content of diamond is in the mnge hem 1% to 10%, the toughness of the composite fits the equation KIC = cexp(a+bx). The constants c, a, and b determined experimentally are 10-6, d.47 and 9.70 respectively.展开更多
We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge_2Sb_2Te_5(GST).The novel perfect...We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge_2Sb_2Te_5(GST).The novel perfect absorber scheme consists of an array of high-index strong-absorbance GST square resonators separated from a continuous Au substrate by a low-index lossless dielectric layer(silica)and a high-index GST planar cavity.Three absorption peaks with the maximal absorbance up to 99.94% are achieved,owing to the excitation of plasmon-like dipolar or quadrupole resonances from the high-index GST resonators and cavity resonances generated by the GST planar cavity.The intensities and positions of the absorption peaks show strong dependence on structural parameters.A heat transfer model is used to investigate the temporal variation of temperature within the GST region.The results show that the temperature of amorphous GST can reach up to 433 K of the phase transition temperature from room temperature in just 0.37 ns with a relatively low incident light intensity of 1.11×10~8W∕m^2,due to the enhanced ultra-broadband light absorbance through strong plasmon resonances and cavity resonance in the absorber.The study suggests a feasible means to lower the power requirements for photonic devices based on a thermal phase change via engineering ultra-broadband light absorbers.展开更多
It is challenging to cooperatively improve the nonlinear optical(NLO)efficiency and the laser-induced damage threshold(LIDT).This work reports a novel IR NLO materials CsInP_(2)S_(7)(CIPS)designed by combination the s...It is challenging to cooperatively improve the nonlinear optical(NLO)efficiency and the laser-induced damage threshold(LIDT).This work reports a novel IR NLO materials CsInP_(2)S_(7)(CIPS)designed by combination the strategies of alkali metals substitution and microscopic NLO units PS4 introduction based on AgGaS_(2).CIPS was composed of strongly distorted[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers constructed by corner-sharing[PS_(4)]^(3-),which increase the NLO efficiency and decrease thermal expansion anisotropy simultaneously.Compared with AgGaS_(2),CIPS exhibited strong phase matchable NLO response ca.1.1×AGS@2.1μm,high LIDT ca.20.8×AgGaS_(2),and IR transparency up to 15.3μm.Structural analysis and theoretical investigation confirmed that large SHG effect and ultrahigh LIDT of CIPS originated from the synergistic contribution of[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers.These results indicate that CIPS is a promising NLO candidate in the mid-IR region,and this study provides a new approach for developing potential NLO-LIDT compatible materials.展开更多
A review is made of the physics and technology of spectrally selective thermal detectors,especially those operating at non-cryogenic temperatures.The background radiation noise fluctuations are rederived for arbitrary...A review is made of the physics and technology of spectrally selective thermal detectors,especially those operating at non-cryogenic temperatures.The background radiation noise fluctuations are rederived for arbitrary spectral characteristics.Infrared absorption due to phonons and free carriers is discussed followed by a review of published works on artificial infrared absorption materials such as patterned grids,nanoparticles,plasmonic structures,metamaterials and others.Subsequently,the literature of the spectral characteristics of broadband thermal detectors and spectrally selective thermal detectors is reviewed.Finally,the authors speculate on the directions that future research and development in the area will take regarding architectures,sensitivity and spectral characteristics.展开更多
Optoelectronic functional crystal materials are crucial components in laser systems and could be applied as polarized light converters,modulators,photorefractive devices,window materials etc.Borates and chalcogenides ...Optoelectronic functional crystal materials are crucial components in laser systems and could be applied as polarized light converters,modulators,photorefractive devices,window materials etc.Borates and chalcogenides are well-established sources of ultraviolet (UV) and infrared (IR) optoelectronic functional crystal materials.The selenoborate system combines the structural diversity of borates with the extensive optical transmission range of metal selenides,showing potential as IR functional materials.However,research on selenoborates remains limited.This review aims to stimulate further research into IR optoelectronic functional crystal materials within the selenoborate system.First,this work offers a comprehensive review of all selenoborates (21) reported to date,categorizing them according to their structural motifs from zero to three dimensions.Second,the unique synthesis methods of selenoborates are summarized.Additionally,first-principles calculations are utilized to analyze the bandgaps and nonlinear optical (NLO) properties of these materials.As a result,it is concluded that selenoborates possess considerable potential for further investigation as IR functional materials,especially in terms of the structures and properties regulated by excellent microstructural groups.展开更多
Crystal structure regulation and optical performance enhancement are huge challenges,especially for the laborious and inefficient trial-and-error method,in the research on infrared nonlinear optical(IR NLO)materials.I...Crystal structure regulation and optical performance enhancement are huge challenges,especially for the laborious and inefficient trial-and-error method,in the research on infrared nonlinear optical(IR NLO)materials.In this work,multi-step cation substitutions were adopted to modulate the crystal structure for the effective design of well-performing IR NLO materials.Specifically,starting from the famous AgGaS_(2)(AGS,I42d)crystal,Ag_(2)CdSiS_(4)(Pmn2_(1))with diamond-like crystal structure,BaAg_(2)SiS_(4)(I42m)with threedimensional tunnel structure and LaAgSiS_(4)(Ama2)with two-dimensional layer structure were designed and experimentally synthesized through multi-step cation substitutions.Structural analysis reveals the fundamental reason of their tetrahedral framework transformation:the size effect of cations and the reduction of component tetrahedra caused by cationic substitution change the assembly mode of the tetrahedral units.Additionally,three non-centrosymmetric Ag-based thiosilicates exhibit wide transmittance range(0.5-17μm),higher laser-induced damage thresholds(2 times that of AGS)and significant phase-matchable second harmonic generation(SHG)enhancement from 0.6 to 3.2 times that of AGS.This work demonstrates that multi-step cation substitution is an effective way to extend non-centrosymmetric structures,which facilitate the exploration of potential infrared nonlinear optical materials.展开更多
Exploration of new material systems and optical performance enhancement are huge challenges for the study of infrared nonlinear optical(IR NLO)materials.In this work,the first thioborate-thiogermanate and thioborate-t...Exploration of new material systems and optical performance enhancement are huge challenges for the study of infrared nonlinear optical(IR NLO)materials.In this work,the first thioborate-thiogermanate and thioborate-thiostannate compounds,Ca_(2)La(Ge_(0.72)Si_(0.28)S_(4))(BS_(3))and Ca_(2)La(Sn_(0.75)Si_(0.25)S_(4))(BS_(3)),containing both co-occupied Ca^(2+)/La^(3+)cation and[Ge/SiS_(4)]^(4-)or[Sn/SiS_(4)]^(4-)anion sites,respectively,were designed through an atomic site co-occupancy strategy.They inherited favourable 3D network structures in which the effectively aligned[MS_(4)]^(4-)and[BS_(3)]^(3-)functional anions were bridged by Ca^(2+)/La^(3+)cations.Remarkably,the title compounds achieved excellent IR NLO properties,including good chemical and thermal stabilities,wide light transmission ranges(0.45-11μm),strong second harmonic generation responses(1.5 and 2.0 times that of commercial AgGaS2 at 2.05μm)and high laser-induced damage thresholds(7 and 6 times that of AgGaS2).Theoretical calculation and experimental results revealed that,on the basis of excellent structural framework,introducing more active functional groups through atomic site co-occupancy could simultaneously enhance the second harmonic generation effect and maintain a relatively high laser-induced damage threshold.This work not only offers an easier synthetic route for mixed anionic thioborates but also provides inspiration for the design of well-performed NLO materials.展开更多
Infrared nonlinear optical(NLO)materials are crucial to the development of laser technology.However,finding ways to effectively synthesize them is still a big challenge.Herein,aided by a stable open framework,four IR ...Infrared nonlinear optical(NLO)materials are crucial to the development of laser technology.However,finding ways to effectively synthesize them is still a big challenge.Herein,aided by a stable open framework,four IR NLO materials,MMn_(6)Ga_(6)S_(16)(M=Ca,Sr,Ba,and Pb),have been effectively synthesized in a high-temperature vacuum sealing system.They all crystallize in a non-centrosymmetric(NCS)space group,P6¯,and their structures feature a three-dimensional open framework composed of Mn-S single and double chains and Ga-S single and double chains,in which these one-dimensional chains increase the structural flexibility and adjustability to accommodate varied cations with different ionic radii.Remarkably,MMn_(6)Ga_(6)S_(16)(M=Ca,Sr,Ba,and Pb)exhibit not only comprehensive NLO performances including appropriate NLO responses and band gaps and a wide transmission range but also para-magnetism in magnetic properties,indicating that MMn_(6)Ga_(6)S_(16)(M=Ca,Sr,Ba,and Pb)are potential IR multifunctional materials.This work suggests that a stable open framework can be used to construct varied structures,which brings a new platform for effectively designing multifunctional materials.展开更多
Infrared nonlinear optical(IR-NLO)materials play a vital role in generating IR laser output and have significant applications in the fields of communication,medicine,and security.At present,commercial IR-NLO crystals ...Infrared nonlinear optical(IR-NLO)materials play a vital role in generating IR laser output and have significant applications in the fields of communication,medicine,and security.At present,commercial IR-NLO crystals suffer from various performance drawbacks that constrain their range of applications.Therefore,the pursuit of designing and exploring new IR-NLO materials has emerged as an important avenue for the advancement of the IR laser industry.Benefiting from the various structural compositions,wide energy gaps,sufficient second-harmonic-generation intensities,strong laser-induced damage thresholds and favorable phase matching features,Mg-based IR-NLO materials have attracted wide attention in recent years.However,there has not been a specific review of this attractive family.展开更多
The performance of infrared(IR)nonlinear optical(NLO)materials is significantly affected by the thermal conductivity kL,but studies on the structure and property relationship of kL in these materials are very rare.In ...The performance of infrared(IR)nonlinear optical(NLO)materials is significantly affected by the thermal conductivity kL,but studies on the structure and property relationship of kL in these materials are very rare.In this work we evaluated the k_(L) in IR NLO multicomponent chalcogenides Li_(x)Ag_(1-x)Ga_(y)In_(1-y)Se_(2) with a smooth change in the compositions x and y by using a machine learning approach and laser flash measurements,combined with available experimental results.The found patterns of kL dependence on the atomic mass,bond length and electronegativity provide an effective understanding for navigation in the process of searching for new chalcogenide crystals with an optimal set of parameters that allow them to be effectively used as a frequency converter of laser radiation in the IR range.Moreover,the compositions Li_(0.5)Ag_(0.5)GaSe_(2),Li_(0.81)Ag_(0.19)InSe_(2) and AgGa_(0.5)In_(0.5)Se_(2) are demonstrated to exhibit a balanced combination of the parameters kL,NLOeffects,energy band gaps,and birefringence for IR NLO applications.展开更多
Infrared(IR)nonlinear optical(NLO)materials with simultaneous strong NLO coefficient and high laserinduced damaged threshold(LIDT)are the urgently desired optical performance NLO materials in laser application.Here,tw...Infrared(IR)nonlinear optical(NLO)materials with simultaneous strong NLO coefficient and high laserinduced damaged threshold(LIDT)are the urgently desired optical performance NLO materials in laser application.Here,two different electropositive alkali elements are concurrently incorporated into a tetrahedral GaS_(4) anionic framework,affording the first polar quaternary sulphide CsLiGa_(6)S_(10)(CLGS)with mixed ordered alkali cations through the solid-state method.CLGS displays a wide band gap(3.25 eV)originating from the GaS_(4) anionic framework and assistant of the‘dimensional reduction’effect by involving two alkali cations.This merit,accompanied by extremely small anisotropy of the thermal expansion of crystal CLGS(0.05)enhances the LIDT(51.0 MW cm^(2))of 4.5 times that of benchmark AgGaS_(2)(11.3 MW cm^(2))at 1064 nm with the pulse width of 10 ns.Phase CLGS adopts a diamond-like anionic framework in which all tetrahedra are arranged in a highly oriented manner,providing a critical contribution to modest second-harmonic generation 0.7 times that of AgGaS_(2) with a phase-matchable behaviour at the 1910 nm laser.These attributes,along with broad transmittance,warrant the further exploration of potential IR NLO chalcogenides containing multiple alkali cations.展开更多
Developing high-performance infrared(IR)nonlinear optical(NLO)materials is essential for modern laser technology,but challenging due to the competition of the NLO coefficient and band gap in the structure.Based on the...Developing high-performance infrared(IR)nonlinear optical(NLO)materials is essential for modern laser technology,but challenging due to the competition of the NLO coefficient and band gap in the structure.Based on the“electronic structure engineering bucket effect”and systematic experimental investigations on the A^(Ⅱ)B^(Ⅱ)C^(Ⅳ)D_(4)^(Ⅵ)family,three new alkaline earth metal sulfides Mg_(0.6)Cd_(1.4)GeS_(4),CaCdGeS_(4),and BaZnGeS_(4)have been developed.The compounds show a structural change from the Pnma(CaCdGeS_(4))to the Fdd2(BaZnGeS_(4))space group.Among them,BaZnGeS_(4)exhibits a phase-matching NLO response of~0.8×AGS,a wide band gap of 3.36 eV,and a high laser-induced damage threshold of~5.4×AGS,achieving a good balance between the NLO response and band gap,which makes it an excellent IR NLO material.Theoretical calculations show that the NLO effects of BaZnGeS_(4)originated from the[ZnS_(4)]and[GeS_(4)]NLO-active motifs.The results indicate that BaZnGeS_(4)is a promising anti-laser damage IR NLO material and enriches the chemical diversity of the A^(Ⅱ)B^(Ⅱ)C^(Ⅳ)D_(4)^(Ⅵ)family.展开更多
基金supported by the National Natural Science Foundation of China (No.50572007)
文摘Erosion test of some infrared （IR） optical crystals （Ge, ZnS, MgF2, and quartz） was conducted with a number of different erodents （glass bead, and angular SiC, SiO2, Al2O3） by a homemade gas-blasting erosion tester. The influence of impact angle, impact velocity, erodent, and erosion time on the erosion rate and the effect of erosion on their IR transmittance were studied. The dam- aged surface morphology was characterized by scanning electron microscopy, and the erosion mechanism was explored. All of the materials show the maximum in wear versus impact angle at 90°, confirming their brittle failure behavior. It is found that the erosion rate is dependent on the erodent velocity by a power law, and it is highly correlated to the hardness of the erodent. The erosion rate-time curves do not show an incubation state, but an accelerated erosion period followed a maximum erosion （steady state）. The decrease of IR transmittance is direct proportion to the erosion rate. Although the material loss occurs primarily by brittle process, ductile behavior is clearly an important feature, especially for MgF2 and ZnS.
基金Funded by the Program for New Century Excellent Talents in University (11-0687)the National Natural Science Foundation of China (51172169)the Fundamental Research Funds for the Central Universities (Wuhan University of Technology)
文摘We investigated image processing algorithms of the original infrared glass flaw image. Using the Laplacian edge enhancement following LSD （Line Segment Detector） algorithm, we can get a good flaw image very consistent with the original one. This study is very helpful to further enhance the infrared glass flaw inspection technique.
基金supported by the Key Research and Development Program of Hebei Province(No.21351501D)A Provincial and Ministerial Scientific Research Project(LJ20212C031165)Basic Frontier Science and Technology Innovation Project of Army Engineering University of PLA(KYSZJQZL2210)。
文摘Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target products were characterized by thermogravimetric analyzer,X-ray diffrotometer,fourier transform infrared spectrometer,scanning electron microscope,spectrophotometer and infrared emissivity tester,and the effects of Er^(3+)doping on its infrared and laser emissivity were studied.At the same time,the Sn_(1−x)Er_(x)O_(2)(x=0%,16%)doping models were constructed based on the first principles of density functional theory,and the related optoelectronic properties such as their energy band structure,density of states,reflectivity and dielectric constant were analyzed,and further explained the mechanism of Er^(3+)doping on SnO_(2)infrared emissivity and laser absorption from the point of electronic structure.The results showed that after calcination at 600℃,single rutile type SnO_(2)was formed,and the crystal structure was not changed by doping Er^(3+).The calcined products showed good fiber morphology,and the average fiber diameter was 402 nm.The infrared emissivity and resistivity of the samples both decreased first and then increased with the increase of Er^(3+)doping amount.When x=16%,the infrared emis-sivity of the sample was at least 0.71;and Er^(3+)doping can effectively reduce the reflectivity of SnO_(2)at 1.06μm and 1.55μm,when x=16%,its reflectivity at 1.06μm and 1.55μm are 50.5%and 40%,respectively,when x=24%,the reflectivity at 1.06μm and 1.55μm wavelengths are 47.3%and 42.1%,respectively.At the same time,the change of carrier concentration and electron transition before and after Er^(3+)doping were described by first-principle calculation,and the regulation mechanism of infrared emissivity and laser reflectivity was explained.This study provides a certain experimental and theoretical basis for the development of a single-type,light-weight and easily prepared infrared and laser compatible-stealth material.
基金supported by the National Natural Science Foundation of China(52303156)the Shenzhen Science and Technology Program(KQTD20180411143514543)+2 种基金the Open Fund of State Key Laboratory of Infrared Physics(SITP-NLIST-YB-2022-02)the Guangdong Basic and Applied Basic Research Foundation(2021A1515110634)the National Training Program of Innovation and Entrepreneurship for Undergraduates(202410701093).
文摘Artificial adaptive soft infrared(IR)materials,mimicking the color-changing abilities observed in soft organisms such as cephalopods,hold significant promise in various emerging technologies,including unconventional flexible displays,intelligent camouflage systems,and advanced sensors.In this study,we integrated inherently deformable liquid metal(LM)microdroplets randomly into an elastomer matrix,creating a fully soft material that exhibits elastic compliance akin to soft biological tissue and adaptive IR-reflecting properties in response to compression.Under compressive strains,each LM inclusion behaves as a unit of dynamic IR reflector,transitioning between a contracted droplet with a corrugated surface and an expanded plate-like filler with a relatively smooth surface.These alterations in shape,size,and surface structure allow dynamic modulation of incident IR radiation's reflection,resulting in reversible changes in IR color(i.e.,detected temperature).This mechanism replicates the dynamic alterations observed in cephalopod skin,where chromatophores dynamically manipulate visible light reflection by changing their size and morphology.We demonstrate proof-of-concept applications of this material,showing its ability to modify IR appearance through compression for visualization,with its localized color-change mechanism enabling its use as a tactile sensor in vision-based tactile grippers.These illustrate the potential of this material in emerging adaptive flexible electronics.
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the support from the National Key Research and Development Program of China[2018YFA0703400].
文摘The infrared conformal window is one of the most critical components in aircraft.Conformal windows with high performance bring low aberrations,high aerodynamic performance,reliability in extreme working environments,and added value for aircraft.Through the past decades,remarkable advances have been achieved in manufacturing technologies for conformal windows,where the machining accuracy approaches the nanometer level,and the surface form becomes more complex.These advances are critical to aircraft development,and these manufacturing technologies also have significant reference values for other directions of the ultra-precision machining field.In this review,the infrared materials suitable for manufacturing conformal windows are introduced and compared with insights into their performances.The remarkable advances and concrete work accomplished by researchers are reviewed.The challenges in manufacturing conformal windows that should be faced in the future are discussed.
基金supported by the High-level Talent Project of Xinjiang Uygur Autonomous Region(2020000039)National Natural Science Foundation of China(52002398,61835014,51972336)Xinjiang Key Laboratory of Electronic Information Materials and Devices(2017D04029).
文摘As the core device of all-solid-state laser,infrared(IR)nonlinear optical(NLO)material plays a critical role in exploring new coherent lights by frequency conversion technologies,which are widely used in noninvasive medical diagnostics,spectroscopy,environmental monitoring and long-distance laser communication.To satisfy the growing demand of current laser technology in IR regions,high performance NLO materials with large second-harmonic generation(SHG)response,high laser-induced damage threshold(LIDT)and wide transparency range are highly expected.Recently,numerous efforts and advances have been achieved in sulfide system.This review highlights the progress of high-performance sulfide IR NLO materials with a good balance between strong SHG response(≥1.0×AgGaS_(2))and wide band gap(≥3.0 eV)since 2018.The chemical synthesis,crystal structure,optical properties and structure-property relationship of 13 high performance metal sulfide IR NLO materials are summarized and reviewed in detail.Finally,the potential opportunities and challenges in IR NLO materials are discussed.
基金Project supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China （No. 51121004）, and the Fundamental Research Funds for the Central Universities （No. HIT.BRETIV.201315）, China
文摘Hypersonic vehicles subjected to strong aerodynamic forces and serious aerodynamic heating require more stringent design for an infrared window. In this paper, a finite element analysis is used to present the distributions of thermal and stress fields in the infrared window for hypersonic vehicles based on flowfield studies. A theoretical guidance is provided to evaluate the influence of aerodynamic heating and forces on infrared window materials. The aerodynamic heat flux from Mach 3 to Mach 6 flight at an altitude of 15 km in a standard atmosphere is obtained through flowfield analysis. The thermal and stress responses are then investigated under constant heat transfer coefficient boundary conditions for different Mach numbers. The numerical results show that the maximum stress is higher than the material strength at Mach 6, which means a failure of the material may occur. The maximum stress and temperatures are lower than the material strength and melting point under other conditions, so the material is safe.
文摘ZnS-Diatnond cotnPOsites (ZnS/D) were fabricated by hot pressing to obtain a ZnS ithered transparent materials with incmeed toughness. The relations of the mechanical properties and the diomond contents were investigated. It was determined that,when the content of diamond is in the mnge hem 1% to 10%, the toughness of the composite fits the equation KIC = cexp(a+bx). The constants c, a, and b determined experimentally are 10-6, d.47 and 9.70 respectively.
基金973 Program of China(2013CB632704)National Natural Science Foundation of China(NSFC)(11374357,11434017)
文摘We numerically demonstrate a novel ultra-broadband polarization-independent metamaterial perfect absorber in the visible and near-infrared region involving the phase-change material Ge_2Sb_2Te_5(GST).The novel perfect absorber scheme consists of an array of high-index strong-absorbance GST square resonators separated from a continuous Au substrate by a low-index lossless dielectric layer(silica)and a high-index GST planar cavity.Three absorption peaks with the maximal absorbance up to 99.94% are achieved,owing to the excitation of plasmon-like dipolar or quadrupole resonances from the high-index GST resonators and cavity resonances generated by the GST planar cavity.The intensities and positions of the absorption peaks show strong dependence on structural parameters.A heat transfer model is used to investigate the temporal variation of temperature within the GST region.The results show that the temperature of amorphous GST can reach up to 433 K of the phase transition temperature from room temperature in just 0.37 ns with a relatively low incident light intensity of 1.11×10~8W∕m^2,due to the enhanced ultra-broadband light absorbance through strong plasmon resonances and cavity resonance in the absorber.The study suggests a feasible means to lower the power requirements for photonic devices based on a thermal phase change via engineering ultra-broadband light absorbers.
基金the Natural Science Foundation of China(No.22105218).
文摘It is challenging to cooperatively improve the nonlinear optical(NLO)efficiency and the laser-induced damage threshold(LIDT).This work reports a novel IR NLO materials CsInP_(2)S_(7)(CIPS)designed by combination the strategies of alkali metals substitution and microscopic NLO units PS4 introduction based on AgGaS_(2).CIPS was composed of strongly distorted[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers constructed by corner-sharing[PS_(4)]^(3-),which increase the NLO efficiency and decrease thermal expansion anisotropy simultaneously.Compared with AgGaS_(2),CIPS exhibited strong phase matchable NLO response ca.1.1×AGS@2.1μm,high LIDT ca.20.8×AgGaS_(2),and IR transparency up to 15.3μm.Structural analysis and theoretical investigation confirmed that large SHG effect and ultrahigh LIDT of CIPS originated from the synergistic contribution of[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers.These results indicate that CIPS is a promising NLO candidate in the mid-IR region,and this study provides a new approach for developing potential NLO-LIDT compatible materials.
基金The authors would like to acknowledge funding for the work described herein from DARPA,ARO,the Electro-Optics Center,and the University of Minnesota,particularly DARPA/ARO contract W911QX-12-C-0002We would also like to thank the authors and publishers who kindly gave permission to their figures.Finally,we would like to thank Nibir Dhar,John Carrano,Ray Balcerak,Bill Clark,Joe Pelligrino and Andrew Wood for much useful advice over the years.
文摘A review is made of the physics and technology of spectrally selective thermal detectors,especially those operating at non-cryogenic temperatures.The background radiation noise fluctuations are rederived for arbitrary spectral characteristics.Infrared absorption due to phonons and free carriers is discussed followed by a review of published works on artificial infrared absorption materials such as patterned grids,nanoparticles,plasmonic structures,metamaterials and others.Subsequently,the literature of the spectral characteristics of broadband thermal detectors and spectrally selective thermal detectors is reviewed.Finally,the authors speculate on the directions that future research and development in the area will take regarding architectures,sensitivity and spectral characteristics.
基金supported by the National Natural Science Foundation of China(22305264,22335007,61835014)the Xinjiang Major Science and Technology Project(2021A01001)+2 种基金the Natural Science Foundation of the Xinjiang Uygur Autonomous Region(2022D01A333)the Key Laboratory Opening Foundation of the Xinjiang Uygur Autonomous Region(2022D04013)the China Postdoctoral Science Foundation(2023T100679).
文摘Optoelectronic functional crystal materials are crucial components in laser systems and could be applied as polarized light converters,modulators,photorefractive devices,window materials etc.Borates and chalcogenides are well-established sources of ultraviolet (UV) and infrared (IR) optoelectronic functional crystal materials.The selenoborate system combines the structural diversity of borates with the extensive optical transmission range of metal selenides,showing potential as IR functional materials.However,research on selenoborates remains limited.This review aims to stimulate further research into IR optoelectronic functional crystal materials within the selenoborate system.First,this work offers a comprehensive review of all selenoborates (21) reported to date,categorizing them according to their structural motifs from zero to three dimensions.Second,the unique synthesis methods of selenoborates are summarized.Additionally,first-principles calculations are utilized to analyze the bandgaps and nonlinear optical (NLO) properties of these materials.As a result,it is concluded that selenoborates possess considerable potential for further investigation as IR functional materials,especially in terms of the structures and properties regulated by excellent microstructural groups.
基金supported by the National Natural Science Foundation of China(No.22031009,22375201 and 21921001).
文摘Crystal structure regulation and optical performance enhancement are huge challenges,especially for the laborious and inefficient trial-and-error method,in the research on infrared nonlinear optical(IR NLO)materials.In this work,multi-step cation substitutions were adopted to modulate the crystal structure for the effective design of well-performing IR NLO materials.Specifically,starting from the famous AgGaS_(2)(AGS,I42d)crystal,Ag_(2)CdSiS_(4)(Pmn2_(1))with diamond-like crystal structure,BaAg_(2)SiS_(4)(I42m)with threedimensional tunnel structure and LaAgSiS_(4)(Ama2)with two-dimensional layer structure were designed and experimentally synthesized through multi-step cation substitutions.Structural analysis reveals the fundamental reason of their tetrahedral framework transformation:the size effect of cations and the reduction of component tetrahedra caused by cationic substitution change the assembly mode of the tetrahedral units.Additionally,three non-centrosymmetric Ag-based thiosilicates exhibit wide transmittance range(0.5-17μm),higher laser-induced damage thresholds(2 times that of AGS)and significant phase-matchable second harmonic generation(SHG)enhancement from 0.6 to 3.2 times that of AGS.This work demonstrates that multi-step cation substitution is an effective way to extend non-centrosymmetric structures,which facilitate the exploration of potential infrared nonlinear optical materials.
基金supported by the National Natural Science Foundation of China(No.22031009,22375201,and 21921001)the Self-deployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences(CXZX-2022-GH06).
文摘Exploration of new material systems and optical performance enhancement are huge challenges for the study of infrared nonlinear optical(IR NLO)materials.In this work,the first thioborate-thiogermanate and thioborate-thiostannate compounds,Ca_(2)La(Ge_(0.72)Si_(0.28)S_(4))(BS_(3))and Ca_(2)La(Sn_(0.75)Si_(0.25)S_(4))(BS_(3)),containing both co-occupied Ca^(2+)/La^(3+)cation and[Ge/SiS_(4)]^(4-)or[Sn/SiS_(4)]^(4-)anion sites,respectively,were designed through an atomic site co-occupancy strategy.They inherited favourable 3D network structures in which the effectively aligned[MS_(4)]^(4-)and[BS_(3)]^(3-)functional anions were bridged by Ca^(2+)/La^(3+)cations.Remarkably,the title compounds achieved excellent IR NLO properties,including good chemical and thermal stabilities,wide light transmission ranges(0.45-11μm),strong second harmonic generation responses(1.5 and 2.0 times that of commercial AgGaS2 at 2.05μm)and high laser-induced damage thresholds(7 and 6 times that of AgGaS2).Theoretical calculation and experimental results revealed that,on the basis of excellent structural framework,introducing more active functional groups through atomic site co-occupancy could simultaneously enhance the second harmonic generation effect and maintain a relatively high laser-induced damage threshold.This work not only offers an easier synthetic route for mixed anionic thioborates but also provides inspiration for the design of well-performed NLO materials.
基金supported by the National Natural Science Foundation of China(grant no.52322202,52172006 and 22071179)the Natural Science Foundation of Tianjin(grant no.20JCJQJC00060 and 21JCJQJC00090).
文摘Infrared nonlinear optical(NLO)materials are crucial to the development of laser technology.However,finding ways to effectively synthesize them is still a big challenge.Herein,aided by a stable open framework,four IR NLO materials,MMn_(6)Ga_(6)S_(16)(M=Ca,Sr,Ba,and Pb),have been effectively synthesized in a high-temperature vacuum sealing system.They all crystallize in a non-centrosymmetric(NCS)space group,P6¯,and their structures feature a three-dimensional open framework composed of Mn-S single and double chains and Ga-S single and double chains,in which these one-dimensional chains increase the structural flexibility and adjustability to accommodate varied cations with different ionic radii.Remarkably,MMn_(6)Ga_(6)S_(16)(M=Ca,Sr,Ba,and Pb)exhibit not only comprehensive NLO performances including appropriate NLO responses and band gaps and a wide transmission range but also para-magnetism in magnetic properties,indicating that MMn_(6)Ga_(6)S_(16)(M=Ca,Sr,Ba,and Pb)are potential IR multifunctional materials.This work suggests that a stable open framework can be used to construct varied structures,which brings a new platform for effectively designing multifunctional materials.
基金sponsored by the National Natural Science Foundation of China(21771179)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR118)the Natural Science Foundation of Fujian Province(2022L3092 and 2023H0041).
文摘Infrared nonlinear optical(IR-NLO)materials play a vital role in generating IR laser output and have significant applications in the fields of communication,medicine,and security.At present,commercial IR-NLO crystals suffer from various performance drawbacks that constrain their range of applications.Therefore,the pursuit of designing and exploring new IR-NLO materials has emerged as an important avenue for the advancement of the IR laser industry.Benefiting from the various structural compositions,wide energy gaps,sufficient second-harmonic-generation intensities,strong laser-induced damage thresholds and favorable phase matching features,Mg-based IR-NLO materials have attracted wide attention in recent years.However,there has not been a specific review of this attractive family.
基金supported by the National Natural Science Foundation of China(Grant No.22133004)the Ministry of Education and Science of the Russian Federation,Grant FSUS-2025-0011(crystal structure analysis)partly by the state assignment of IGM SB RAS No.122041400031-2(crystal growth).
文摘The performance of infrared(IR)nonlinear optical(NLO)materials is significantly affected by the thermal conductivity kL,but studies on the structure and property relationship of kL in these materials are very rare.In this work we evaluated the k_(L) in IR NLO multicomponent chalcogenides Li_(x)Ag_(1-x)Ga_(y)In_(1-y)Se_(2) with a smooth change in the compositions x and y by using a machine learning approach and laser flash measurements,combined with available experimental results.The found patterns of kL dependence on the atomic mass,bond length and electronegativity provide an effective understanding for navigation in the process of searching for new chalcogenide crystals with an optimal set of parameters that allow them to be effectively used as a frequency converter of laser radiation in the IR range.Moreover,the compositions Li_(0.5)Ag_(0.5)GaSe_(2),Li_(0.81)Ag_(0.19)InSe_(2) and AgGa_(0.5)In_(0.5)Se_(2) are demonstrated to exhibit a balanced combination of the parameters kL,NLOeffects,energy band gaps,and birefringence for IR NLO applications.
基金supported by the National Natural Science Foundation of China(21921001,21827813,92161125,22075283,and 22175172)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2021300)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2020ZZ108,2021ZR205).
文摘Infrared(IR)nonlinear optical(NLO)materials with simultaneous strong NLO coefficient and high laserinduced damaged threshold(LIDT)are the urgently desired optical performance NLO materials in laser application.Here,two different electropositive alkali elements are concurrently incorporated into a tetrahedral GaS_(4) anionic framework,affording the first polar quaternary sulphide CsLiGa_(6)S_(10)(CLGS)with mixed ordered alkali cations through the solid-state method.CLGS displays a wide band gap(3.25 eV)originating from the GaS_(4) anionic framework and assistant of the‘dimensional reduction’effect by involving two alkali cations.This merit,accompanied by extremely small anisotropy of the thermal expansion of crystal CLGS(0.05)enhances the LIDT(51.0 MW cm^(2))of 4.5 times that of benchmark AgGaS_(2)(11.3 MW cm^(2))at 1064 nm with the pulse width of 10 ns.Phase CLGS adopts a diamond-like anionic framework in which all tetrahedra are arranged in a highly oriented manner,providing a critical contribution to modest second-harmonic generation 0.7 times that of AgGaS_(2) with a phase-matchable behaviour at the 1910 nm laser.These attributes,along with broad transmittance,warrant the further exploration of potential IR NLO chalcogenides containing multiple alkali cations.
基金supported by the High-level Talent Project of Xinjiang Uygur Autonomous Region(2020000039)the National Natural Science Foundation of China(52002398,61835014,and 51972336)+1 种基金the West Light Foundation of the CAS(2019-YDYLTD-002)the Xinjiang Key Laboratory of Electronic Information Materials and Devices(2017D04029).
文摘Developing high-performance infrared(IR)nonlinear optical(NLO)materials is essential for modern laser technology,but challenging due to the competition of the NLO coefficient and band gap in the structure.Based on the“electronic structure engineering bucket effect”and systematic experimental investigations on the A^(Ⅱ)B^(Ⅱ)C^(Ⅳ)D_(4)^(Ⅵ)family,three new alkaline earth metal sulfides Mg_(0.6)Cd_(1.4)GeS_(4),CaCdGeS_(4),and BaZnGeS_(4)have been developed.The compounds show a structural change from the Pnma(CaCdGeS_(4))to the Fdd2(BaZnGeS_(4))space group.Among them,BaZnGeS_(4)exhibits a phase-matching NLO response of~0.8×AGS,a wide band gap of 3.36 eV,and a high laser-induced damage threshold of~5.4×AGS,achieving a good balance between the NLO response and band gap,which makes it an excellent IR NLO material.Theoretical calculations show that the NLO effects of BaZnGeS_(4)originated from the[ZnS_(4)]and[GeS_(4)]NLO-active motifs.The results indicate that BaZnGeS_(4)is a promising anti-laser damage IR NLO material and enriches the chemical diversity of the A^(Ⅱ)B^(Ⅱ)C^(Ⅳ)D_(4)^(Ⅵ)family.
