A series of selective solar absorber coatings of Cr-Cr_(2)O_(3)were deposited in different content on stainless steel by plasma spraying.The samples were annealed at different temperatures.The optical performance(both...A series of selective solar absorber coatings of Cr-Cr_(2)O_(3)were deposited in different content on stainless steel by plasma spraying.The samples were annealed at different temperatures.The optical performance(both the solar absorptance and the thermal emittance)were studied by spectrophotometry.The surface morphology,the structure and the surface roughness were investigated by scanning electron microscopy(SEM),X-ray diffraction(XRD),and roughmeter respectively.The results show that,as the content of Cr increased,the solar absorptance(α)decreased greatly,from 0.91 to 0.84.Meanwhile,the thermal emittance(ε)decreased more greatly,from 0.86 to about 0.64.The ratio between the solar absorptance and the thermal emittance increased from 1.06 to 1.31.Annealing had a great impact on the optical performance.Annealing temperature is an important element.But its influence was a little complex.To pure Cr coating,annealing at 500℃was a perfect chosen,where the ratio between the solar absorptance and the thermal emittance was highest of 1.46.展开更多
From different reports, it （AZO） and indium-doped including usage areas. We nanocrystalline films with is realized that there is a need to consider all sides of aluminum-doped zinc oxide zinc oxide （IZO） thin film...From different reports, it （AZO） and indium-doped including usage areas. We nanocrystalline films with is realized that there is a need to consider all sides of aluminum-doped zinc oxide zinc oxide （IZO） thin films with their optical, luminescence and surface properties establish an assessment to carry out further information to summarize AZO and IZO impact of the layer number.展开更多
One-dimensional strontium hydroxyapatite （Sr-HAp） nanorods were successfully synthesized by a simple solvothermal method. The products were characterized via X-ray diffraction （XRD）, Fourier transform infrared （....One-dimensional strontium hydroxyapatite （Sr-HAp） nanorods were successfully synthesized by a simple solvothermal method. The products were characterized via X-ray diffraction （XRD）, Fourier transform infrared （.FT-IR）, .cold field emission.sc.anning.elec.tron microscopy_.（FESEM）, transmission.electron microscopy （TEM）,photoluminescence （PL） excitation and emission spectra. The experimental results indicated that oleic acid as a surfactant played a key role in confining the growth of the Sr-HAp powders. A possible formation mechanism of the one-dimensional nanorod was proposed and elaborated. Moreover, the as-obtained Sr-HAp samoles showed an intense and bright emission band centered at 460 nm under long-wavelength UV light excitation and the contents of NaOH used in the synthetic process had an obvious impact on the optical performance of Sr-HAp powders. The possible luminescent mechanism of the Sr-HAp samples was discussed.展开更多
In optical performance monitoring system,the analog to digital converter is needed to detect the peak of nanosecond pulse and get the signal envelope.A scheme based on a designed anti-aliasing filter and analog to dig...In optical performance monitoring system,the analog to digital converter is needed to detect the peak of nanosecond pulse and get the signal envelope.A scheme based on a designed anti-aliasing filter and analog to digital converter is proposed to broaden the nanosecond pulse and make it easier for the analog to digital converter to catch the peak of the nanosecond pulse.The experimental results demonstrate that,with the proposed scheme,the optical performance system needs less time to get the recovered eye-diagram of high speed optical data signal,and is robust to phase mismatch in the analog to digital converter circuit.展开更多
To find out the influence of technological parameters on optical performance of fused optical fiber device, the fiber coupler was served as subject investigated by using the fused biconical taper machining as experime...To find out the influence of technological parameters on optical performance of fused optical fiber device, the fiber coupler was served as subject investigated by using the fused biconical taper machining as experimental setup. Fused fiber coupler's optical performances such as insertion loss, excess loss, directivity and uniformity were tested with the optical test system that was constituted of tunable laser and optical spectrum analyzer. Especially the relationship between optical performance and drawing speed was investigated. The experimental results show that the optical performance is closely related to process conditions. At fused temperature of 1 200 ℃, there exists a drawing speed of 150 μms, which makes the device's performance optimum. Out of this speed region, the optical performance drops quickly. At drawing speed of 200 μms, the excess loss is relatively small when the fused temperature is above 1 200 ℃. So the technological parameters have close relationship with optical performance of the coupler, and the good performance coupler can't get until the drawing speed and fused temperature match accurately.展开更多
Rare-earth(RE)doping is one of the valid approaches to optimize the optical performance of the CsPbBr_(3)perovskite.However,the underlying mechanism and the role of the RE_4f electrons are still unknown,which are sign...Rare-earth(RE)doping is one of the valid approaches to optimize the optical performance of the CsPbBr_(3)perovskite.However,the underlying mechanism and the role of the RE_4f electrons are still unknown,which are significant for the development of advanced RE-doped perovskite materials.Considering these,a series of CsPbBr_(3):RE(RE=Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb)compounds were studied by applying first-principles calculations.Based on the analysis of the phase stability diagram,we found that RE doping in the bulk CsPbBr_(3)leads to the formation of the REPb defect.Meanwhile,the two types of electric-dipole allowed transition were revealed by exploring the electronic structure.We also demonstrated that the doped systems retain the defect tolerance nature of the host and the RE_4f electrons enrich the band-edge states,which are the main origins for luminescence enhancement.Our current contribution not only presents physical insight into the role of RE_4f electrons in luminescence,but also provides a guideline for designing the targeted RE-doped perovskites.展开更多
The element with the strongest electropositivity,Cs,was introduced into an anionic framework[Ga_(9)S_(16)]5−constructed from GaS4 tetrahedra,which are functional nonlinear optical motifs,to acquire the ternary noncent...The element with the strongest electropositivity,Cs,was introduced into an anionic framework[Ga_(9)S_(16)]5−constructed from GaS4 tetrahedra,which are functional nonlinear optical motifs,to acquire the ternary noncentrosymmetric sulphide Cs_(5)Ga_(9)S_(16)through solid-state reaction in a silica tube.Similar to classic LiGaS_(2),the three-dimensional phase Cs_(5)Ga_(9)S_(16)displayed prominent nonlinear optical performance,such as second-harmonic generation intensity(equal to LiGaS_(2))with phase-matching behaviour under incident laser irradiation at 1064 and 1910 nm,a wide band gap(3.81 eV)for a high laser-induced damage threshold(equal to LiGaS_(2)@1064 nm),and broad infrared transmittance transparency.Importantly,the Li-free Cs_(5)Ga_(9)S_(16)avoided the problem of corrosiveness to silica tubes at high temperatures similar to LiGaS_(2),suggesting that Cs_(5)Ga_(9)S_(16)could be a promising candidate for infrared nonlinear optical applications.展开更多
In the present work,an improved hot injection technique,namely microwave-assisted hot injection,for mass production of Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3))perovskite nanocrystals(NCs)was reported.This strategy...In the present work,an improved hot injection technique,namely microwave-assisted hot injection,for mass production of Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3))perovskite nanocrystals(NCs)was reported.This strategy combines the advantages of both microwave irradiation and hot injection,which represents characteristics such as homogeneous heating and rapid production of Mn^(2+):CsPbCl_(3)NCs with a homogeneous size distribution.Meanwhile,it exhibits the capacity for gram-scale synthesis of Mn^(2+):CsPbCl_(3)NCs.The Mn^(2+)doping concentrations can be facilely tailored by controlling the reaction temperatures and feed ratios of the MnCl_(2)precursor,resulting in their enhanced optical properties with a PL QY up to 65%,which is the highest among the Mn^(2+)-doped perovskite NCs ever reported.The as-constructed light emitting diodes(LEDs)based on Mn^(2+):CsPbCl_(3)NCs emit highly bright white light,suggesting their potential applications in optoelectronic devices.展开更多
Infrared(IR)nonlinear optical(NLO)materials have attracted tremendous interest for civil and military applications,but it remains a great contemporary challenge to develop high-effciency NLO crystals that possess suff...Infrared(IR)nonlinear optical(NLO)materials have attracted tremendous interest for civil and military applications,but it remains a great contemporary challenge to develop high-effciency NLO crystals that possess suffciently high second-harmonic generation(SHG)effciencies coupled to wide transparency ranges and high laser damage thresholds.A series of new hydrous rare-earth iodates RE(IO_(3))_(3)·(H_(2)O)(RE=Y 1,Eu 2)and La_(2)(IO_(3))_(6)(H_(2)O)(3)have been synthesized through facile hydrothermal methods.1 and 2 are isostructural,crystallizing in the polar space group P21,while 3 crystallizes in the polar space group Pc.1-3 feature three-dimensional(3D)frameworks composed of alternately connected corner-shared dis torted[REO_(x)]polyhedra(RE=Y,Eu,and La;x=8,9)and[IO_(3)]^(−)groups.Optical studies showed that 1–3 exhibit good NLO properties,including strong SHG intensities(3.0×(1),4.5×(2),and 1.5×KH_(2)PO_(4)(3)),large band gaps(4.12(1),4.36(2),and 4.24 eV(3),with 2 possessing the largest band gap among the known SHG-active rare-earth-based iodates,high laser damage thresholds(LDT)(53×(1),43×(2),and 44×AgGaS_(2)(3)),and wide transparency ranges(ca.3.0–11.3μm)in the mid-IR region covering two criti cal IR transparency windows;1–3 are therefore potential candidate NLO materials.Density functional theory calculations on 1–3 confirm that their strong SHG responses and large band gaps are mainly derived from the synergistic effect of[IO_(3)]^(−)groups and rare-earth oxide polyhedra[REOx]in their 3D frameworks.We conclude that the introduction of rare-earth cations with moderate electropositivity into iodates may optimize the balance between SHG effciency and optical band gaps,the key requirement for high-performance NLO materials for practical applications.展开更多
A new alkali metal borate fluoride Li_(3)KB_(9)O_(15)F has been successfully obtained by the high-temperature solution method in open air for the first time.An X-ray crystallographic study reveals that it crystallizes...A new alkali metal borate fluoride Li_(3)KB_(9)O_(15)F has been successfully obtained by the high-temperature solution method in open air for the first time.An X-ray crystallographic study reveals that it crystallizes in the trigonal space group R3c(no.161),a=11.974(4)Å,b=11.974(4)Å,c=15.998(11)Åand Z=6.It exhibits a complicated three-dimensional(3D)network composed of LiO_(3)F,KO_(6)F distorted polyhedra and 3D B–O framework.展开更多
Correction for‘KPb_(3)(_(3)-C_(5)H_(4)NCOO)_(2)Cl_(5):a brand-new stable lead chloride with good comprehensive nonlinear optical performance’by Wen-Xiu Bao et al.,Inorg.Chem.Front.,_(2)0_(2)_(2),9,18_(3)0–18_(3)_(5...Correction for‘KPb_(3)(_(3)-C_(5)H_(4)NCOO)_(2)Cl_(5):a brand-new stable lead chloride with good comprehensive nonlinear optical performance’by Wen-Xiu Bao et al.,Inorg.Chem.Front.,_(2)0_(2)_(2),9,18_(3)0–18_(3)_(5),https://doi.org/10.10_(3)9/D_(2)QI00171C.展开更多
Axially coordinated metal-porphyrin-functionalized multi-walled carbon nanotube （MWCNT） nanohybrids were prepared via two different synthetic approaches （a one-pot 1,3-dipolar cycloaddition reaction and a stepwise ...Axially coordinated metal-porphyrin-functionalized multi-walled carbon nanotube （MWCNT） nanohybrids were prepared via two different synthetic approaches （a one-pot 1,3-dipolar cycloaddition reaction and a stepwise approach that involved 1,3-dipolar cycloaddition followed by nucleophilic substitution）, and characterized through spectroscopic techniques. Attachment of the tin porphyrins to the surface of the MWCNTs significantly improves their solubility and ease of processing. These axially coordinated （5,10,15,20-tetraphenylporphyrinato）tin（Ⅳ） （SnTPP）- MWCNTs exhibit significant fluorescence quenching. The third-order nonlinear optical properties of the resultant nanohybrids were studied by using the Z-scan technique at 532 nm with both nanosecond and picosecond laser pulses. The results show that the nanohybrids exhibit significant reverse saturable absorption or saturable absorption when nanosecond or picosecond pulses, respectively, are employed. Improvement in the nanosecond regime nonlinear absorption is observed on proceeding to the nanohybrids and is ascribed to a combination of the outstanding properties of MWCNTs and the chemically attached metal-porphyrins.展开更多
The optical performance of a receiver has a great influence on the efficiency and stability of a solar thermal power system.Most of the literature focuses on the optical performance of receivers with different geometr...The optical performance of a receiver has a great influence on the efficiency and stability of a solar thermal power system.Most of the literature focuses on the optical performance of receivers with different geometric shapes,but less research is conducted on the effects of critical geometric parameters.In this paper,the commercial software TracePro was used to investigate the effects of some factors on a conical cavity receiver,such as the conical angle,the number of loops of the helical tube,and the distance between the focal point of the collector and the aperture.These factors affect the optical efficiency,the maximum heat flux density,and the light distribution in the conical cavity.The optical performance of the conical receiver was studied and analyzed using the Monte Carlo ray tracing method.To make a reliable simulation,the helical tube was attached to the inner wall of the cavity in the proposed model.The results showed that the amount of light rays reaching the helical tube increases with the increasing of the conical angle,while the optical efficiency decreases and the maximum heat flux density increases.The increase in the number of loops contributed to an increase in the optical efficiency and a uniform light distribution.The conical cavity receiver had an optimal optical performance when the focal point of the collector was near the aperture.展开更多
A multifocal metalens,which focuses incident light at multiple foci,has many applications in imaging systems and optical communications.However,the traditional design strategy of a multifocal metalens combines several...A multifocal metalens,which focuses incident light at multiple foci,has many applications in imaging systems and optical communications.However,the traditional design strategy of a multifocal metalens combines several lenses that have different focal points into a planar integrated unit,resulting in low imaging quality because of the high background noise.Here we show that the defects of the traditional method can be overcome by designing a metalens with conic shapes(the ellipse and the hyperbola);this approach could improve the imaging performance and substantially decrease the background noise of multifocal metalenses.These benefits arise from the intrinsic properties of the two conic curves,which can focus incident light constructively at all of the foci of the metalens.We further demonstrate that the proposed conicshaped metalens can function well within a broadband operation wavelength that ranges from 600 to 900 nm with the dual polarity actively controlled by the incident circular polarized light.The great agreement between the experimental and simulation results demonstrates that our proposed metalens has significant potential for use in future integrated nanophotonic devices.展开更多
Boron-doped aluminum nitride （B-AlN） thin films were synthesized on Al substrates by using chemical vapor deposition method by changing the synthesis parameters and were used as thermal interface material for high p...Boron-doped aluminum nitride （B-AlN） thin films were synthesized on Al substrates by using chemical vapor deposition method by changing the synthesis parameters and were used as thermal interface material for high power light emitting diode （LED）. The B-AlN thin film-coated Al substrate was used as heat sink and studied the performance of high power LED at various driving currents. The recorded transient cooling curve was evaluated to study the rise in junction temperature （Tj）, total thermal resistance （gth_tot） and the substrate thermal resistance （Rth_sub） of the given LED. From the results, the B-AlN thin film （prepared at process 4） interfaced LED showed low Rth-tot and Tj value for all driving currents and observed high difference in Rth_tot （△Rth_tot =2.2 K/W） at 700 mA when compared with the Rth-tot of LED attached on bare Al substrates （LED/Al）. The Tj of LED was reduced considerably and observed 4.7 ℃ as ATj for the film prepared using process 4 condition when compared with LED/Al boundary condition at 700 mA. The optical performance of LED was also tested for all boundary conditions and showed improved lux values for the given LED at 700 mA where B-AlN thin film was synthesized using optimized flow of Al, B and N sources with minimized B and N content. The other optical parameters such as color correlated temperature and color rendering index were also measured and observed low difference for all boundary conditions. The observed results are suggested to use B-AlN thin film as efficient solid thin film thermal interface materials in high power LED.展开更多
Large-scale dense wavelength division multiplexing(DWDM)multi-channel performance monitoring is one of the indispensable technologies for the flexible optical networks.The existing Labelbased monitoring scheme require...Large-scale dense wavelength division multiplexing(DWDM)multi-channel performance monitoring is one of the indispensable technologies for the flexible optical networks.The existing Labelbased monitoring scheme requires expensive optical demultiplexing components/equipment to avoid the influence of stimulated Raman scattering(SRS),which is not only costly and bulky,but also could not monitor the wavelength channels simultaneously.In this paper,a low-cost,high-accuracy monitoring scheme based on Optical Label Method is proposed for DWDM networks,where the optical channel power and node identification(ID),as the main monitoring targets that both can indicate or evaluate the channel connection status,could be efficiently monitored.In the scheme,a novel digital signal processing(DSP)method of SRS mitigation is proposed and demonstrated,and an asynchronous code-division multiple access(A-CDMA)based digital label encoding and decoding method is adopted to distinguish the node ID so that channel initial added node can be accurately verified,thereby wavelength connection status can be reliably monitored by combining the channel power and node ID information.The simulation results show that each wavelength channel power and node ID can be accurately monitored only by low bandwidth photoelectric detector(PD)under the condition of 80 wavelengths and 10 spans at C-band.展开更多
The outstanding properties of CVD diamond film such as electronic, optical, thermal and mechanical and the high radiation hardness have made it an ideal candidate material for radiation detectors in severe environment...The outstanding properties of CVD diamond film such as electronic, optical, thermal and mechanical and the high radiation hardness have made it an ideal candidate material for radiation detectors in severe environments. Fabrication of ＇detector grade＇ CVD diamond films and development of CVD diamond detectors have been leading edge subjects. Micro-strip gas chamber （MSGC） fabricated on CVD diamond substrate would overcome the charge-up effect and the substrate instability, which has been a hotspot in the research of gas detectors.展开更多
Aiming at the problem of large fading noise in Rayleigh Brillouin optical time domain analysis system, a wavelength scanning technique is proposed to enhance the performance of the temperature sensing system. The prin...Aiming at the problem of large fading noise in Rayleigh Brillouin optical time domain analysis system, a wavelength scanning technique is proposed to enhance the performance of the temperature sensing system. The principle of the proposed technique to reduce the fading noise is introduced based on the analysis of Rayleigh Brillouin optical time domain analysis system. The experimental results show that the signal-to-noise ratio(SNR) at the end of optical fiber with length of 50 m after 17 times wavelength scanning is 5.21 d B higher than that with single wavelength, the Brillouin frequency shift(BFS) on the heated fiber with length of 70 m inserted at the center of sensing fiber can be accurately measured as 0.19 MHz, which is equivalent to a measurement accuracy of 0.19 °C. It indicates that the proposed technique can realize high-accuracy temperature measurement and has huge potential in the field of long-distance and high-accuracy sensing.展开更多
Copper indium sulfur-based quantum dots(CIS QDs)are classified as one of well-known ternaryⅠ-Ⅲ-Ⅵsemiconductors,which have exciting promising applications in display and lighting devices,due to their unique merits s...Copper indium sulfur-based quantum dots(CIS QDs)are classified as one of well-known ternaryⅠ-Ⅲ-Ⅵsemiconductors,which have exciting promising applications in display and lighting devices,due to their unique merits such as non-toxicity,stability,and high photoluminescence quantum yield(PL QY).However,the emission full width at half maximum(FWHM)of CIS-based QDs typically extends to~140 nm,fundamentally limiting their use in high-color-purity light emitting.Herein,we report the rationally-designed CIS QDs with high efficiency and narrowband emission by chemical stoichiometry and gradient shell engineering,based on precisely controlling the dynamic growth and stoichiometric ratio.It is found that the accurate control on the growth kinetics and stoichiometry during the nucleation process of CIS QDs could enhance the crystallinity through gradual and organized crystalline growth,which effectively mitigates the formation of InCusubstitutional and Cu vacancies,thus suppressing the defect emission.Furthermore,the introduced InSx/ZnxGa_(1-x)S gradient shell on the surface of QDs cores could reduce the strain within interface,thereby eliminating the non-radiative recombination caused by the surface defects resulted from interface strain.As a result,a remarkable PLQY of 89%is achieved for the QDs.More importantly,their FWHM decreases to 70 nm,which is the narrowest one for CIS-based QDs ever reported,representing their bright future to be applied in high-definition display devices.展开更多
We investigate the microstructures of the pure aluminium foil and filter used on the space solar telescope, irradiated by photons with different doses. The vacancy defect clusters induced by proton irradiation in both...We investigate the microstructures of the pure aluminium foil and filter used on the space solar telescope, irradiated by photons with different doses. The vacancy defect clusters induced by proton irradiation in both samples are characterized by transmission electron microscopy, and the density and the size distribution of vacancy defect clusters are determined. Their transmittances are measured before and after irradiating the samples by protons with energy E = 100 keV and dose φ = 6 × 10^11/mm^2. Our experimental results show that the density and the size of vacancy defect clusters increase with the increase of irradiation doses in the irradiated pure aluminium foils. As irradiation dose increases, vacancies incline to form larger defect clusters. In the irradiated filter, a large number of banded void defects are observed at the agglomerate boundary, which results in the degradation of the optical and mechanical performances of the filter after proton irradiation.展开更多
文摘A series of selective solar absorber coatings of Cr-Cr_(2)O_(3)were deposited in different content on stainless steel by plasma spraying.The samples were annealed at different temperatures.The optical performance(both the solar absorptance and the thermal emittance)were studied by spectrophotometry.The surface morphology,the structure and the surface roughness were investigated by scanning electron microscopy(SEM),X-ray diffraction(XRD),and roughmeter respectively.The results show that,as the content of Cr increased,the solar absorptance(α)decreased greatly,from 0.91 to 0.84.Meanwhile,the thermal emittance(ε)decreased more greatly,from 0.86 to about 0.64.The ratio between the solar absorptance and the thermal emittance increased from 1.06 to 1.31.Annealing had a great impact on the optical performance.Annealing temperature is an important element.But its influence was a little complex.To pure Cr coating,annealing at 500℃was a perfect chosen,where the ratio between the solar absorptance and the thermal emittance was highest of 1.46.
文摘From different reports, it （AZO） and indium-doped including usage areas. We nanocrystalline films with is realized that there is a need to consider all sides of aluminum-doped zinc oxide zinc oxide （IZO） thin films with their optical, luminescence and surface properties establish an assessment to carry out further information to summarize AZO and IZO impact of the layer number.
基金Supported by the National Natural Science Foundation of China (20876157)the Fundamental Research Funds for the Central Universities (FRF-BR-10-002A)
文摘One-dimensional strontium hydroxyapatite （Sr-HAp） nanorods were successfully synthesized by a simple solvothermal method. The products were characterized via X-ray diffraction （XRD）, Fourier transform infrared （.FT-IR）, .cold field emission.sc.anning.elec.tron microscopy_.（FESEM）, transmission.electron microscopy （TEM）,photoluminescence （PL） excitation and emission spectra. The experimental results indicated that oleic acid as a surfactant played a key role in confining the growth of the Sr-HAp powders. A possible formation mechanism of the one-dimensional nanorod was proposed and elaborated. Moreover, the as-obtained Sr-HAp samoles showed an intense and bright emission band centered at 460 nm under long-wavelength UV light excitation and the contents of NaOH used in the synthetic process had an obvious impact on the optical performance of Sr-HAp powders. The possible luminescent mechanism of the Sr-HAp samples was discussed.
基金supported by National 863 Program of China(2013AA013401),P.R.ChinaNational Natural Science Foundation of China under Grant No.61177067,No.61027007,and No.61331010
文摘In optical performance monitoring system,the analog to digital converter is needed to detect the peak of nanosecond pulse and get the signal envelope.A scheme based on a designed anti-aliasing filter and analog to digital converter is proposed to broaden the nanosecond pulse and make it easier for the analog to digital converter to catch the peak of the nanosecond pulse.The experimental results demonstrate that,with the proposed scheme,the optical performance system needs less time to get the recovered eye-diagram of high speed optical data signal,and is robust to phase mismatch in the analog to digital converter circuit.
基金Project (50605063) supported by the National Natural Science Foundation of ChinaProject(NCET-040753) supported by New Century Excellent Talents in University of ChinaProject (20050533037) supported by the Doctoral Program of Higher Education of China
文摘To find out the influence of technological parameters on optical performance of fused optical fiber device, the fiber coupler was served as subject investigated by using the fused biconical taper machining as experimental setup. Fused fiber coupler's optical performances such as insertion loss, excess loss, directivity and uniformity were tested with the optical test system that was constituted of tunable laser and optical spectrum analyzer. Especially the relationship between optical performance and drawing speed was investigated. The experimental results show that the optical performance is closely related to process conditions. At fused temperature of 1 200 ℃, there exists a drawing speed of 150 μms, which makes the device's performance optimum. Out of this speed region, the optical performance drops quickly. At drawing speed of 200 μms, the excess loss is relatively small when the fused temperature is above 1 200 ℃. So the technological parameters have close relationship with optical performance of the coupler, and the good performance coupler can't get until the drawing speed and fused temperature match accurately.
基金the financial aid from the National Key Research and Development Program of China(2016YFB0701003)the National Natural Science Foundation of China(21871248 and 21590794)+3 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(Y201947)the Key Research Program of Frontier Sciences,AS(YZDY-SSW-JSC018)the K.C.Wong Education Foundation(GJTD-2018-09)the Jilin Province Science and Technology Development Plan Project(20180101172JC).
文摘Rare-earth(RE)doping is one of the valid approaches to optimize the optical performance of the CsPbBr_(3)perovskite.However,the underlying mechanism and the role of the RE_4f electrons are still unknown,which are significant for the development of advanced RE-doped perovskite materials.Considering these,a series of CsPbBr_(3):RE(RE=Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb)compounds were studied by applying first-principles calculations.Based on the analysis of the phase stability diagram,we found that RE doping in the bulk CsPbBr_(3)leads to the formation of the REPb defect.Meanwhile,the two types of electric-dipole allowed transition were revealed by exploring the electronic structure.We also demonstrated that the doped systems retain the defect tolerance nature of the host and the RE_4f electrons enrich the band-edge states,which are the main origins for luminescence enhancement.Our current contribution not only presents physical insight into the role of RE_4f electrons in luminescence,but also provides a guideline for designing the targeted RE-doped perovskites.
基金supported by the National Natural Science Foundation of China(Grant No.21827813,21921001,22175172,22075283,92161125)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2020303,2021300)+1 种基金the Natural Science Foundation of Fujian Provinces,China(Grant No.2020J01115)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(Grant no.2021ZR205).
文摘The element with the strongest electropositivity,Cs,was introduced into an anionic framework[Ga_(9)S_(16)]5−constructed from GaS4 tetrahedra,which are functional nonlinear optical motifs,to acquire the ternary noncentrosymmetric sulphide Cs_(5)Ga_(9)S_(16)through solid-state reaction in a silica tube.Similar to classic LiGaS_(2),the three-dimensional phase Cs_(5)Ga_(9)S_(16)displayed prominent nonlinear optical performance,such as second-harmonic generation intensity(equal to LiGaS_(2))with phase-matching behaviour under incident laser irradiation at 1064 and 1910 nm,a wide band gap(3.81 eV)for a high laser-induced damage threshold(equal to LiGaS_(2)@1064 nm),and broad infrared transmittance transparency.Importantly,the Li-free Cs_(5)Ga_(9)S_(16)avoided the problem of corrosiveness to silica tubes at high temperatures similar to LiGaS_(2),suggesting that Cs_(5)Ga_(9)S_(16)could be a promising candidate for infrared nonlinear optical applications.
基金supported by the National Natural Science Foundation for Excellent Young Scholars of China(Grant No.51522402)the National Natural Science Foundation of China(NSFC,Grant No.51572133,51672137 and 51702175)+1 种基金the Zhejiang Provincial Nature Science Foundation(Grant No.LQ17E020002)the and Natural Science Foundation of Ningbo Municipal Government(Grant No.2017A610002).
文摘In the present work,an improved hot injection technique,namely microwave-assisted hot injection,for mass production of Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3))perovskite nanocrystals(NCs)was reported.This strategy combines the advantages of both microwave irradiation and hot injection,which represents characteristics such as homogeneous heating and rapid production of Mn^(2+):CsPbCl_(3)NCs with a homogeneous size distribution.Meanwhile,it exhibits the capacity for gram-scale synthesis of Mn^(2+):CsPbCl_(3)NCs.The Mn^(2+)doping concentrations can be facilely tailored by controlling the reaction temperatures and feed ratios of the MnCl_(2)precursor,resulting in their enhanced optical properties with a PL QY up to 65%,which is the highest among the Mn^(2+)-doped perovskite NCs ever reported.The as-constructed light emitting diodes(LEDs)based on Mn^(2+):CsPbCl_(3)NCs emit highly bright white light,suggesting their potential applications in optoelectronic devices.
基金supported by the National Natural Science Foundation of China(no.51432006)the Ministry of Education of China for the Changjiang Innovation Research Team(no.IRT13R24)+1 种基金the Ministry of Education and the State Administration of Foreign Experts Affairs for the 111 Project(no.B13025)the Innovation Program of Shanghai Municipal Education Commission.M.G.H.and C.Z.thank the Australian Research Council for support(DP170100411).
文摘Infrared(IR)nonlinear optical(NLO)materials have attracted tremendous interest for civil and military applications,but it remains a great contemporary challenge to develop high-effciency NLO crystals that possess suffciently high second-harmonic generation(SHG)effciencies coupled to wide transparency ranges and high laser damage thresholds.A series of new hydrous rare-earth iodates RE(IO_(3))_(3)·(H_(2)O)(RE=Y 1,Eu 2)and La_(2)(IO_(3))_(6)(H_(2)O)(3)have been synthesized through facile hydrothermal methods.1 and 2 are isostructural,crystallizing in the polar space group P21,while 3 crystallizes in the polar space group Pc.1-3 feature three-dimensional(3D)frameworks composed of alternately connected corner-shared dis torted[REO_(x)]polyhedra(RE=Y,Eu,and La;x=8,9)and[IO_(3)]^(−)groups.Optical studies showed that 1–3 exhibit good NLO properties,including strong SHG intensities(3.0×(1),4.5×(2),and 1.5×KH_(2)PO_(4)(3)),large band gaps(4.12(1),4.36(2),and 4.24 eV(3),with 2 possessing the largest band gap among the known SHG-active rare-earth-based iodates,high laser damage thresholds(LDT)(53×(1),43×(2),and 44×AgGaS_(2)(3)),and wide transparency ranges(ca.3.0–11.3μm)in the mid-IR region covering two criti cal IR transparency windows;1–3 are therefore potential candidate NLO materials.Density functional theory calculations on 1–3 confirm that their strong SHG responses and large band gaps are mainly derived from the synergistic effect of[IO_(3)]^(−)groups and rare-earth oxide polyhedra[REOx]in their 3D frameworks.We conclude that the introduction of rare-earth cations with moderate electropositivity into iodates may optimize the balance between SHG effciency and optical band gaps,the key requirement for high-performance NLO materials for practical applications.
基金supported by the Xinjiang International Science&Technology Cooperation Program(Grant No.2017E01014)Tianshan Innovation Team Program(Grant No.2018D14001)the National Natural Science Foundation of China(Grant No.U1703132)+6 种基金the Tianshan Xue Song Program“Xinjiang Youth Top Talent Backup Project”(Grant No.2017XS17),the National Key Research Project(Grant No.2016YFB1102302,2016YFB0402104)the Science and Technology Project of Urumqi(Grant No.P161010002)the Xinjiang Key Research and Development Program(Grant No.2016B02021)the Major Program of Xinjiang Uygur Autonomous Region of China during the 13th Five-Year Plan Period(Grant No.2016A02003)the West Light Foundation of the Chinese Academy of Sciences(Grant No.2016-YJRC-2)the Foundation of Director of XTIPC,CAS(Grant No.2016PY004)the Tianshan Xue Song Program“Xinjiang Youth Top Talent Backup Project”(Grant No.2017XS17).
文摘A new alkali metal borate fluoride Li_(3)KB_(9)O_(15)F has been successfully obtained by the high-temperature solution method in open air for the first time.An X-ray crystallographic study reveals that it crystallizes in the trigonal space group R3c(no.161),a=11.974(4)Å,b=11.974(4)Å,c=15.998(11)Åand Z=6.It exhibits a complicated three-dimensional(3D)network composed of LiO_(3)F,KO_(6)F distorted polyhedra and 3D B–O framework.
文摘Correction for‘KPb_(3)(_(3)-C_(5)H_(4)NCOO)_(2)Cl_(5):a brand-new stable lead chloride with good comprehensive nonlinear optical performance’by Wen-Xiu Bao et al.,Inorg.Chem.Front.,_(2)0_(2)_(2),9,18_(3)0–18_(3)_(5),https://doi.org/10.10_(3)9/D_(2)QI00171C.
基金Financial support from the National Natural Science Foundation of China （Nos. 51432006, 50925207, and 51172100）, the Ministry of Science and Technology of China for the International Science Linkages Program （No. 2011DFG52970）, the Ministry of Education of China for the Changjiang Innovation Research Team （No. IRT14R23）, the Ministry of Education and the State Administration of Foreign Experts Affairs for the 111 Project （No. B13025）, 100 Talents Program of CAS, and Jiangsu Innovation Research Team are gratefully acknowledged. M. G. H., M. P. C., and C. Z. thank the Australian Research Council （ARC） for support.
文摘Axially coordinated metal-porphyrin-functionalized multi-walled carbon nanotube （MWCNT） nanohybrids were prepared via two different synthetic approaches （a one-pot 1,3-dipolar cycloaddition reaction and a stepwise approach that involved 1,3-dipolar cycloaddition followed by nucleophilic substitution）, and characterized through spectroscopic techniques. Attachment of the tin porphyrins to the surface of the MWCNTs significantly improves their solubility and ease of processing. These axially coordinated （5,10,15,20-tetraphenylporphyrinato）tin（Ⅳ） （SnTPP）- MWCNTs exhibit significant fluorescence quenching. The third-order nonlinear optical properties of the resultant nanohybrids were studied by using the Z-scan technique at 532 nm with both nanosecond and picosecond laser pulses. The results show that the nanohybrids exhibit significant reverse saturable absorption or saturable absorption when nanosecond or picosecond pulses, respectively, are employed. Improvement in the nanosecond regime nonlinear absorption is observed on proceeding to the nanohybrids and is ascribed to a combination of the outstanding properties of MWCNTs and the chemically attached metal-porphyrins.
文摘The optical performance of a receiver has a great influence on the efficiency and stability of a solar thermal power system.Most of the literature focuses on the optical performance of receivers with different geometric shapes,but less research is conducted on the effects of critical geometric parameters.In this paper,the commercial software TracePro was used to investigate the effects of some factors on a conical cavity receiver,such as the conical angle,the number of loops of the helical tube,and the distance between the focal point of the collector and the aperture.These factors affect the optical efficiency,the maximum heat flux density,and the light distribution in the conical cavity.The optical performance of the conical receiver was studied and analyzed using the Monte Carlo ray tracing method.To make a reliable simulation,the helical tube was attached to the inner wall of the cavity in the proposed model.The results showed that the amount of light rays reaching the helical tube increases with the increasing of the conical angle,while the optical efficiency decreases and the maximum heat flux density increases.The increase in the number of loops contributed to an increase in the optical efficiency and a uniform light distribution.The conical cavity receiver had an optimal optical performance when the focal point of the collector was near the aperture.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0206000)National Basic Research Program of China(973 Program,Grant No.2015CB932403,2017YFA0205700)+2 种基金the National Science Foundation of China(Grant No.61422501,11674012,11374023,61176120,61378059 and 61521004)the Foundation for the Author of the National Excellent Doctoral Dissertation of PR China(Grant No.201420)the National Program for Support of Top-notch Young Professionals.
文摘A multifocal metalens,which focuses incident light at multiple foci,has many applications in imaging systems and optical communications.However,the traditional design strategy of a multifocal metalens combines several lenses that have different focal points into a planar integrated unit,resulting in low imaging quality because of the high background noise.Here we show that the defects of the traditional method can be overcome by designing a metalens with conic shapes(the ellipse and the hyperbola);this approach could improve the imaging performance and substantially decrease the background noise of multifocal metalenses.These benefits arise from the intrinsic properties of the two conic curves,which can focus incident light constructively at all of the foci of the metalens.We further demonstrate that the proposed conicshaped metalens can function well within a broadband operation wavelength that ranges from 600 to 900 nm with the dual polarity actively controlled by the incident circular polarized light.The great agreement between the experimental and simulation results demonstrates that our proposed metalens has significant potential for use in future integrated nanophotonic devices.
基金financially supported by Collaborative Research in Engineering, Science and Technology (CREST) under Grant No. 304/PFIZIK/650601/C121
文摘Boron-doped aluminum nitride （B-AlN） thin films were synthesized on Al substrates by using chemical vapor deposition method by changing the synthesis parameters and were used as thermal interface material for high power light emitting diode （LED）. The B-AlN thin film-coated Al substrate was used as heat sink and studied the performance of high power LED at various driving currents. The recorded transient cooling curve was evaluated to study the rise in junction temperature （Tj）, total thermal resistance （gth_tot） and the substrate thermal resistance （Rth_sub） of the given LED. From the results, the B-AlN thin film （prepared at process 4） interfaced LED showed low Rth-tot and Tj value for all driving currents and observed high difference in Rth_tot （△Rth_tot =2.2 K/W） at 700 mA when compared with the Rth-tot of LED attached on bare Al substrates （LED/Al）. The Tj of LED was reduced considerably and observed 4.7 ℃ as ATj for the film prepared using process 4 condition when compared with LED/Al boundary condition at 700 mA. The optical performance of LED was also tested for all boundary conditions and showed improved lux values for the given LED at 700 mA where B-AlN thin film was synthesized using optimized flow of Al, B and N sources with minimized B and N content. The other optical parameters such as color correlated temperature and color rendering index were also measured and observed low difference for all boundary conditions. The observed results are suggested to use B-AlN thin film as efficient solid thin film thermal interface materials in high power LED.
基金supported by the National Natural Science Foundation of China(No.62001045)Fund of State Key Laboratory of IPOC(BUPT)(No.IPOC2021ZT17)。
文摘Large-scale dense wavelength division multiplexing(DWDM)multi-channel performance monitoring is one of the indispensable technologies for the flexible optical networks.The existing Labelbased monitoring scheme requires expensive optical demultiplexing components/equipment to avoid the influence of stimulated Raman scattering(SRS),which is not only costly and bulky,but also could not monitor the wavelength channels simultaneously.In this paper,a low-cost,high-accuracy monitoring scheme based on Optical Label Method is proposed for DWDM networks,where the optical channel power and node identification(ID),as the main monitoring targets that both can indicate or evaluate the channel connection status,could be efficiently monitored.In the scheme,a novel digital signal processing(DSP)method of SRS mitigation is proposed and demonstrated,and an asynchronous code-division multiple access(A-CDMA)based digital label encoding and decoding method is adopted to distinguish the node ID so that channel initial added node can be accurately verified,thereby wavelength connection status can be reliably monitored by combining the channel power and node ID information.The simulation results show that each wavelength channel power and node ID can be accurately monitored only by low bandwidth photoelectric detector(PD)under the condition of 80 wavelengths and 10 spans at C-band.
文摘The outstanding properties of CVD diamond film such as electronic, optical, thermal and mechanical and the high radiation hardness have made it an ideal candidate material for radiation detectors in severe environments. Fabrication of ＇detector grade＇ CVD diamond films and development of CVD diamond detectors have been leading edge subjects. Micro-strip gas chamber （MSGC） fabricated on CVD diamond substrate would overcome the charge-up effect and the substrate instability, which has been a hotspot in the research of gas detectors.
基金supported by the National Natural Science Foundation of China(No.61377088)the Natural Science Foundation of Hebei Province of China(Nos.E2015502053 and F2015502059)the Fundamental Research Funds for the Central Universities(No.2016XS104)
文摘Aiming at the problem of large fading noise in Rayleigh Brillouin optical time domain analysis system, a wavelength scanning technique is proposed to enhance the performance of the temperature sensing system. The principle of the proposed technique to reduce the fading noise is introduced based on the analysis of Rayleigh Brillouin optical time domain analysis system. The experimental results show that the signal-to-noise ratio(SNR) at the end of optical fiber with length of 50 m after 17 times wavelength scanning is 5.21 d B higher than that with single wavelength, the Brillouin frequency shift(BFS) on the heated fiber with length of 70 m inserted at the center of sensing fiber can be accurately measured as 0.19 MHz, which is equivalent to a measurement accuracy of 0.19 °C. It indicates that the proposed technique can realize high-accuracy temperature measurement and has huge potential in the field of long-distance and high-accuracy sensing.
基金supported by“Science and Technology Innovation 2025”of Ningbo Foundation(No.2020Z061)the general scientific research project of the Department of Education of Zhejiang Province(Nos.Y202147973 and Y202250313)+2 种基金Scientific Research Project Funded by Ningbo University of Technology(Nos.2022KQ11 and 2022TS26)National Natural Science Foundation of China(No.62165001)the special fund for“Guangxi Bagui Scholars”。
文摘Copper indium sulfur-based quantum dots(CIS QDs)are classified as one of well-known ternaryⅠ-Ⅲ-Ⅵsemiconductors,which have exciting promising applications in display and lighting devices,due to their unique merits such as non-toxicity,stability,and high photoluminescence quantum yield(PL QY).However,the emission full width at half maximum(FWHM)of CIS-based QDs typically extends to~140 nm,fundamentally limiting their use in high-color-purity light emitting.Herein,we report the rationally-designed CIS QDs with high efficiency and narrowband emission by chemical stoichiometry and gradient shell engineering,based on precisely controlling the dynamic growth and stoichiometric ratio.It is found that the accurate control on the growth kinetics and stoichiometry during the nucleation process of CIS QDs could enhance the crystallinity through gradual and organized crystalline growth,which effectively mitigates the formation of InCusubstitutional and Cu vacancies,thus suppressing the defect emission.Furthermore,the introduced InSx/ZnxGa_(1-x)S gradient shell on the surface of QDs cores could reduce the strain within interface,thereby eliminating the non-radiative recombination caused by the surface defects resulted from interface strain.As a result,a remarkable PLQY of 89%is achieved for the QDs.More importantly,their FWHM decreases to 70 nm,which is the narrowest one for CIS-based QDs ever reported,representing their bright future to be applied in high-definition display devices.
基金Project supported by the National Natural Science Foundation of China (Grant No. 50671042)the Program for Innovative Research Team of Jangsu University and the Program for Exellent Talents of Jangsu University (Grant No. 07JDG032)
文摘We investigate the microstructures of the pure aluminium foil and filter used on the space solar telescope, irradiated by photons with different doses. The vacancy defect clusters induced by proton irradiation in both samples are characterized by transmission electron microscopy, and the density and the size distribution of vacancy defect clusters are determined. Their transmittances are measured before and after irradiating the samples by protons with energy E = 100 keV and dose φ = 6 × 10^11/mm^2. Our experimental results show that the density and the size of vacancy defect clusters increase with the increase of irradiation doses in the irradiated pure aluminium foils. As irradiation dose increases, vacancies incline to form larger defect clusters. In the irradiated filter, a large number of banded void defects are observed at the agglomerate boundary, which results in the degradation of the optical and mechanical performances of the filter after proton irradiation.
