Deep-ultraviolet(deep-UV)nonlinear optical(NLO)crystals are of current interest because they play an indis-pensable role in modern scientific equipment.Searching these crystals was traditionally limited toπ-conjugate...Deep-ultraviolet(deep-UV)nonlinear optical(NLO)crystals are of current interest because they play an indis-pensable role in modern scientific equipment.Searching these crystals was traditionally limited toπ-conjugated systems,such as borates and carbonates.In 2019,our group reported two non-π-conjugated sulfates as new sources of deep-UV NLO crystals for the first time.In this mini review,we provide a comprehensive overview of the recent development of non-π-conjugated NLO sulfates with deep-UV absorption edge in aspect of synthesis methods,crystal structures,thermal stability,and optical performance.Besides,we conclude the crucial structure-property relationships,and further give some prospects for exploring non-π-conjugated NLO sulfates with deep-UV absorption edge with high thermal stability,enhanced second-order NLO effects,birefringence,etc.We believe that this mini review will not only facilitate researchers to design superior non-π-conjugated NLO sulfates with deep-UV absorption edge but also shed useful insights on the explorations of other non-π-conjugated deep-UV NLO crystal systems.展开更多
As structural variants of famous hexagonal tungsten bronzes,hexagonal tungsten oxides(HTO)represent an important family with fascinating functional properties,such as piezoelectric,ferroelectric,pyroelectric,and nonli...As structural variants of famous hexagonal tungsten bronzes,hexagonal tungsten oxides(HTO)represent an important family with fascinating functional properties,such as piezoelectric,ferroelectric,pyroelectric,and nonlinear optical(NLO)properties.However,none of them are transparent in the deep-UV spectral region,which limits their applications.Herein,we report the first HTO-type monofluorophosphate K_(3)Sc_(3)(PO_(4))(PO_(3)F)_(2)F_(5)(I)with deep-UV transparency.Such a monofluorophosphate is NLO-active with a phase-matchable powder second harmonic generation efficiency of 0.9 times that of KH_(2)PO_(4)at 1,064 nm.Importantly,the UV-Vis reflectance spectrum indicates that it is deep-UV transparent down to 200 nm.This work pushes the transparent window of NLO materials with HTO-type structures down to the deep-UV spectral region for the first time and opens up a new door for HTO materials.展开更多
A novel fluorescence lifetime imaging microscopy(FLIM) working with deep UV 240–280 nm wavelength excitations has been developed. UV-FLIM is used for measurement of defect-related fluorescence and its changes upon an...A novel fluorescence lifetime imaging microscopy(FLIM) working with deep UV 240–280 nm wavelength excitations has been developed. UV-FLIM is used for measurement of defect-related fluorescence and its changes upon annealing from femtosecond laser-induced modifications in fused silica. This FLIM technique can be used with microfluidic and biosamples to characterize temporal characteristics of fluorescence upon UV excitation, a capability easily added to a standard microscope-based FLIM. UV-FLIM was tested to show annealing of the defects induced by silica structuring with ultrashort laser pulses. Frequency-domain fluorescence measurements were converted into the time domain to extract long fluorescence lifetimes from defects in silica.展开更多
The forbidden pitch "dip" in the critical dimension (CD) through the pitch curve is a well-known optical proximity effect. The CD and CD process window near the "dip",usually found near a pitch range of 1.1 to 1...The forbidden pitch "dip" in the critical dimension (CD) through the pitch curve is a well-known optical proximity effect. The CD and CD process window near the "dip",usually found near a pitch range of 1.1 to 1.4 wavelength/ NA (numerical aperture),is smaller when compared with other pitches. This is caused by inadequate imaging contrast for an unequal line and space grating. Although this effect is relatively well-known, its relationship with typical process condition parameters,such as the effective image blur caused by the photo-acid diffusion during the post exposure bake or the aberration in the imaging lens, has not been systematically studied. In this paper, we will examine the correlation between the image blur and the effect on the CD, including the decrease in the CD value (the depth of the "dip") and the CD process window. We find that both the decrease in the CD value and the focus latitude near the forbidden pitch correlate very well with the effective Gaussian image blur. Longer effective diffusion length correlates well with a smaller process window and a deeper CD "dip". We conclude that the dip depth is very sensitive to the change in image contrast.展开更多
紫外LED的发光功率和效率还远不能令人们满意,波长短于300 nm的深紫外LED的发光效率普遍较低。厘清高Al组分Al Ga N多量子阱结构的发光机制将有利于探索改善深紫外LED的发光效率的新途径、新方法。为此,本文通过金属有机气相外延技术外...紫外LED的发光功率和效率还远不能令人们满意,波长短于300 nm的深紫外LED的发光效率普遍较低。厘清高Al组分Al Ga N多量子阱结构的发光机制将有利于探索改善深紫外LED的发光效率的新途径、新方法。为此,本文通过金属有机气相外延技术外延生长了表面平整、界面清晰可辨且陡峭的高Al组分AlGa N多量子阱结构材料,并对其进行变温光致发光谱测试,结合数值计算,深入探讨了Al Ga N量子阱的发光机制。研究表明,量子阱中具有很强的局域化效应,其发光和局域激子的跳跃息息相关,而发光的猝灭则与局域激子的解局域以及位错引起的非辐射复合有关。展开更多
基金the National Natural Science Foundation of China(22122507,22193042,21833010,61975207,and 21921001)the Natural Science Foundation of Fujian Province(2022J02012)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y202069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024)Fujian Institute of Innovation(FJCXY18010201)in Chinese Academy of Sciences.
文摘Deep-ultraviolet(deep-UV)nonlinear optical(NLO)crystals are of current interest because they play an indis-pensable role in modern scientific equipment.Searching these crystals was traditionally limited toπ-conjugated systems,such as borates and carbonates.In 2019,our group reported two non-π-conjugated sulfates as new sources of deep-UV NLO crystals for the first time.In this mini review,we provide a comprehensive overview of the recent development of non-π-conjugated NLO sulfates with deep-UV absorption edge in aspect of synthesis methods,crystal structures,thermal stability,and optical performance.Besides,we conclude the crucial structure-property relationships,and further give some prospects for exploring non-π-conjugated NLO sulfates with deep-UV absorption edge with high thermal stability,enhanced second-order NLO effects,birefringence,etc.We believe that this mini review will not only facilitate researchers to design superior non-π-conjugated NLO sulfates with deep-UV absorption edge but also shed useful insights on the explorations of other non-π-conjugated deep-UV NLO crystal systems.
基金supported by the NSFC(21833010,61975207,21921001,21971238,51872297,and 51890864)Youth Innovation Promotion of CAS(202069)+6 种基金the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LYSLH024)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20010200 and XDB20000000)Fujian Institute of Innovation(FJCXY18010201)in Chinese Academy of Sciencesthe National Key Research and Development Program of China(2019YFA0210400)Key Laboratory of Functional Crystals and Laser Technology,TIPC,CAS(FCLT 202003)Key Laboratory of New Processing Technology for Nonferrous Metal&Materials,Ministry of Education/Guangxi Key Laboratory of Optical and Electronic Materials and Devices(20KF-11)Startup Project of Doctor Scientific Research of Jiangxi Normal University(12021319)。
文摘As structural variants of famous hexagonal tungsten bronzes,hexagonal tungsten oxides(HTO)represent an important family with fascinating functional properties,such as piezoelectric,ferroelectric,pyroelectric,and nonlinear optical(NLO)properties.However,none of them are transparent in the deep-UV spectral region,which limits their applications.Herein,we report the first HTO-type monofluorophosphate K_(3)Sc_(3)(PO_(4))(PO_(3)F)_(2)F_(5)(I)with deep-UV transparency.Such a monofluorophosphate is NLO-active with a phase-matchable powder second harmonic generation efficiency of 0.9 times that of KH_(2)PO_(4)at 1,064 nm.Importantly,the UV-Vis reflectance spectrum indicates that it is deep-UV transparent down to 200 nm.This work pushes the transparent window of NLO materials with HTO-type structures down to the deep-UV spectral region for the first time and opens up a new door for HTO materials.
基金support via the Australian Research Council Discovery DP130101205 and DP120102980 grantsproject with Altechna Ltd
文摘A novel fluorescence lifetime imaging microscopy(FLIM) working with deep UV 240–280 nm wavelength excitations has been developed. UV-FLIM is used for measurement of defect-related fluorescence and its changes upon annealing from femtosecond laser-induced modifications in fused silica. This FLIM technique can be used with microfluidic and biosamples to characterize temporal characteristics of fluorescence upon UV excitation, a capability easily added to a standard microscope-based FLIM. UV-FLIM was tested to show annealing of the defects induced by silica structuring with ultrashort laser pulses. Frequency-domain fluorescence measurements were converted into the time domain to extract long fluorescence lifetimes from defects in silica.
文摘The forbidden pitch "dip" in the critical dimension (CD) through the pitch curve is a well-known optical proximity effect. The CD and CD process window near the "dip",usually found near a pitch range of 1.1 to 1.4 wavelength/ NA (numerical aperture),is smaller when compared with other pitches. This is caused by inadequate imaging contrast for an unequal line and space grating. Although this effect is relatively well-known, its relationship with typical process condition parameters,such as the effective image blur caused by the photo-acid diffusion during the post exposure bake or the aberration in the imaging lens, has not been systematically studied. In this paper, we will examine the correlation between the image blur and the effect on the CD, including the decrease in the CD value (the depth of the "dip") and the CD process window. We find that both the decrease in the CD value and the focus latitude near the forbidden pitch correlate very well with the effective Gaussian image blur. Longer effective diffusion length correlates well with a smaller process window and a deeper CD "dip". We conclude that the dip depth is very sensitive to the change in image contrast.
文摘紫外LED的发光功率和效率还远不能令人们满意,波长短于300 nm的深紫外LED的发光效率普遍较低。厘清高Al组分Al Ga N多量子阱结构的发光机制将有利于探索改善深紫外LED的发光效率的新途径、新方法。为此,本文通过金属有机气相外延技术外延生长了表面平整、界面清晰可辨且陡峭的高Al组分AlGa N多量子阱结构材料,并对其进行变温光致发光谱测试,结合数值计算,深入探讨了Al Ga N量子阱的发光机制。研究表明,量子阱中具有很强的局域化效应,其发光和局域激子的跳跃息息相关,而发光的猝灭则与局域激子的解局域以及位错引起的非辐射复合有关。
基金Supported by NSF of China (No 60473133No 10575097)+1 种基金the ' Hundred Talented' Projects from ACS,the 973 Project (No 2006CB303102)the SRFDP (No 20060358050),and the 111 Projects