We report here an optically pumped deep UV edge emitting laser with AlGaN multiple quantum wells(MQWs)active region grown on AlN substrate by low pressure organometallic vapor phase epitaxy(LP-OMVPE)in a high-temperat...We report here an optically pumped deep UV edge emitting laser with AlGaN multiple quantum wells(MQWs)active region grown on AlN substrate by low pressure organometallic vapor phase epitaxy(LP-OMVPE)in a high-temperature reactor.The 21 period Al0.53Ga0.47N/Al0.7Ga0.3N MQWs laser structure was optically pumped using 193 nm deep UV excimer laser source.A laser peak was achieved from the cleaved facets at 280.3 nm with linewidth of 0.08 nm at room temperature with threshold power density of 320 kW/cm^2.The emission is completely TE polarized and the side mode suppression ratio(SMSR)is measured to be around 14 dB at 450 kW/cm^2.展开更多
Herein,two antimony sulfates,named RbSb(SO_(4))_(2)(1)and CsSb(SO_(4))_(2)(2),have been successfully synthesized with the introduction of Sb^(3+)cation with stereochemically active lone pairs(SCALP)into sulfates by th...Herein,two antimony sulfates,named RbSb(SO_(4))_(2)(1)and CsSb(SO_(4))_(2)(2),have been successfully synthesized with the introduction of Sb^(3+)cation with stereochemically active lone pairs(SCALP)into sulfates by the conventional hydrothermal method.Both two compounds endow short ultraviolet(UV)absorption edges(281 nm and 278 nm,respectively)and large birefringence(0.171@546 nm and 0.174@546 nm,respectively),which means that they are promising short-wave UV optical materials.Interestingly,though both of the two compounds exhibit similar 1D chained structures,and possess the same functional moieties including SbO4 seesaws and SO4 tetrahedral groups,they exhibit significantly opposite macroscopic symmetries,i.e.,compound 1 crystallizes in a centrosymmetric(CS)manner(P2_(1)/n)and compound 2 in a noncentrosymmetric(NCS)manner(P2_(1)2_(1)2_(1)),due to the size of cations[r(Rb+)=1.56 A˚,r(Cs+)=1.67 A˚]affects the orientation of SCALP of the adjacent Sb^(3+).展开更多
The ultraviolet(UV) band edge photorefractivity of LiNbO_3:Zr at 325 nm has been investigated. The experimental results show that the resistance against photorefraction at 325 nm is quite obvious but not as strong as ...The ultraviolet(UV) band edge photorefractivity of LiNbO_3:Zr at 325 nm has been investigated. The experimental results show that the resistance against photorefraction at 325 nm is quite obvious but not as strong as that at 351 nm, when the doping concentration of Zr reaches 2.0 mol%. It is reported that the photorefractivity in other tetravalently doped LiNbO_3 crystals, such as LiNbO_3:Hf and Li NbO_3:Sn, is enhanced dramatically with doping concentration over threshold. Here we give an explicit explanation on such seemly conflicting behaviors of tetravalently doped LiNbO_3, which is ascribed to the combined effect of increased photoconductivity and the absorption strength of the band edge photorefractive centers.展开更多
Using cesium lead halide perovskite nanocrystals, CsPb(Cl/Br)3, as a light absorber, we report a highly effective UV and blue light blocking film. The CsPb(Cl/Br)3 nanocrystals are well dispersed in the ethyl cellulos...Using cesium lead halide perovskite nanocrystals, CsPb(Cl/Br)3, as a light absorber, we report a highly effective UV and blue light blocking film. The CsPb(Cl/Br)3 nanocrystals are well dispersed in the ethyl cellulose(EC) matrix to compose a UV and blue light shielding film, and the absorption edge of the film is tunable by adjusting Cl to Br ratio using anion exchange. The CsPbCl2 Br-EC film exhibits a transmittance of 5% at 459 nm, 90% at 478 nm and 95% in the range of 500–800 nm, which makes it excellent for UV and blue light shielding. In addition, the as-prepared EC-CsPb(Cl/Br)3 film shows excellent photostability under UV irradiation. Results demonstrate that this EC-CsPb(Cl/Br)3 based materials with sharp absorbance edges, tunable blocking wavelength, and high photostability can be useful for the applications in UV and blue light blocking and optical filters.展开更多
A new double alkali metal borate,LiRbB8O13,has been obtained in the sealed system.Its structure consists of two kinds of independent interpenetrating 3D frameworks composed of the fundamental building block,[B8O16]8–...A new double alkali metal borate,LiRbB8O13,has been obtained in the sealed system.Its structure consists of two kinds of independent interpenetrating 3D frameworks composed of the fundamental building block,[B8O16]8–.It crystallizes in the P21/c space group with a=10.950(6),b=7.689(4),c=11.375(7)?,β=96.653(7)°,V=951.2(9)?3,Z=4,F(000)=736,Dc=2.702 g/cm3,Mr=386.89 andμ=5.289 mm–1.The final R=0.0547 and w R=0.1224.The UV-Vis-NIR diffuse reflectance spectrum,infrared spectrum and the first-principle theoretical studies show that the title compound possesses a short cut-off edge and large birefringence.展开更多
基金The work was supported by Defense Advanced Research Projects Agency(DARPA)under grant # HR0011-15-2-0002.The program managers are Dr.Daniel Green and Dr.Young-Kai Chen.
文摘We report here an optically pumped deep UV edge emitting laser with AlGaN multiple quantum wells(MQWs)active region grown on AlN substrate by low pressure organometallic vapor phase epitaxy(LP-OMVPE)in a high-temperature reactor.The 21 period Al0.53Ga0.47N/Al0.7Ga0.3N MQWs laser structure was optically pumped using 193 nm deep UV excimer laser source.A laser peak was achieved from the cleaved facets at 280.3 nm with linewidth of 0.08 nm at room temperature with threshold power density of 320 kW/cm^2.The emission is completely TE polarized and the side mode suppression ratio(SMSR)is measured to be around 14 dB at 450 kW/cm^2.
基金the National Natural Science Foundation of China(Nos.22122106,22071158,21971171)the Fundamental Research Funds from Sichuan University(No.2021SCUNL101).
文摘Herein,two antimony sulfates,named RbSb(SO_(4))_(2)(1)and CsSb(SO_(4))_(2)(2),have been successfully synthesized with the introduction of Sb^(3+)cation with stereochemically active lone pairs(SCALP)into sulfates by the conventional hydrothermal method.Both two compounds endow short ultraviolet(UV)absorption edges(281 nm and 278 nm,respectively)and large birefringence(0.171@546 nm and 0.174@546 nm,respectively),which means that they are promising short-wave UV optical materials.Interestingly,though both of the two compounds exhibit similar 1D chained structures,and possess the same functional moieties including SbO4 seesaws and SO4 tetrahedral groups,they exhibit significantly opposite macroscopic symmetries,i.e.,compound 1 crystallizes in a centrosymmetric(CS)manner(P2_(1)/n)and compound 2 in a noncentrosymmetric(NCS)manner(P2_(1)2_(1)2_(1)),due to the size of cations[r(Rb+)=1.56 A˚,r(Cs+)=1.67 A˚]affects the orientation of SCALP of the adjacent Sb^(3+).
基金supported by the Doctoral Foundation of Tianjin Normal University(No.135202XB1607)
文摘The ultraviolet(UV) band edge photorefractivity of LiNbO_3:Zr at 325 nm has been investigated. The experimental results show that the resistance against photorefraction at 325 nm is quite obvious but not as strong as that at 351 nm, when the doping concentration of Zr reaches 2.0 mol%. It is reported that the photorefractivity in other tetravalently doped LiNbO_3 crystals, such as LiNbO_3:Hf and Li NbO_3:Sn, is enhanced dramatically with doping concentration over threshold. Here we give an explicit explanation on such seemly conflicting behaviors of tetravalently doped LiNbO_3, which is ascribed to the combined effect of increased photoconductivity and the absorption strength of the band edge photorefractive centers.
基金financially supported by the National Nature Scientific Foundation of China(No.21675133)and OESACLS201902
文摘Using cesium lead halide perovskite nanocrystals, CsPb(Cl/Br)3, as a light absorber, we report a highly effective UV and blue light blocking film. The CsPb(Cl/Br)3 nanocrystals are well dispersed in the ethyl cellulose(EC) matrix to compose a UV and blue light shielding film, and the absorption edge of the film is tunable by adjusting Cl to Br ratio using anion exchange. The CsPbCl2 Br-EC film exhibits a transmittance of 5% at 459 nm, 90% at 478 nm and 95% in the range of 500–800 nm, which makes it excellent for UV and blue light shielding. In addition, the as-prepared EC-CsPb(Cl/Br)3 film shows excellent photostability under UV irradiation. Results demonstrate that this EC-CsPb(Cl/Br)3 based materials with sharp absorbance edges, tunable blocking wavelength, and high photostability can be useful for the applications in UV and blue light blocking and optical filters.
基金supported by the National Natural Science Foundation of China(61835014,U1703127,51972336)Shanghai Cooperation Organization Science and Technology Partnership Program(2020E01019)+1 种基金Xinjiang Outstanding Young Talents in Science and Technology(2018Q004)Fujian Institute of Innovation,CAS。
文摘A new double alkali metal borate,LiRbB8O13,has been obtained in the sealed system.Its structure consists of two kinds of independent interpenetrating 3D frameworks composed of the fundamental building block,[B8O16]8–.It crystallizes in the P21/c space group with a=10.950(6),b=7.689(4),c=11.375(7)?,β=96.653(7)°,V=951.2(9)?3,Z=4,F(000)=736,Dc=2.702 g/cm3,Mr=386.89 andμ=5.289 mm–1.The final R=0.0547 and w R=0.1224.The UV-Vis-NIR diffuse reflectance spectrum,infrared spectrum and the first-principle theoretical studies show that the title compound possesses a short cut-off edge and large birefringence.
