Exploring a new tuning way to facilely realize single-band red emission in trivalent rare-earth ions(RE3+) doped upconversion(UC) materials is still desirable.In this work,the intense single-band red emission is achie...Exploring a new tuning way to facilely realize single-band red emission in trivalent rare-earth ions(RE3+) doped upconversion(UC) materials is still desirable.In this work,the intense single-band red emission is achieved by co-doping only Ho3+in the BiOCl:Er3+ under 1550 nm excitation.In the BiOCl layered host,co-doping Ho3+can further enhance the red emission and simultaneously suppress the green emission of Er3+,and thus obviously improve the red-to-green(R/G) ratio.It is found that Ho3+does not se rve as ene rgy trapping through the 5 I6 state as in traditional UC materials but acts as ET bridge(4 S3/2,2 H11/2(Er3+)→5 F4,5 S2(Ho3+)→4 F9/2(Er3+)).The tuning mechanism of Ho3+is discussed in detail and further confirms through a comparative experiment.Our research gives an unusual perspective to tune the UC behavior of Er3+through co-doping Ho3+,which might be inspiring for achievement of single-band red UC emission.展开更多
The Ho3＋/yb3＋ co-doped a-NaYF4 single crystal was grown successfully for the first time by a modified Bridgman method in which KF was used as assisting flux and a large temperature gradient （70-90℃ /cm） of solid-...The Ho3＋/yb3＋ co-doped a-NaYF4 single crystal was grown successfully for the first time by a modified Bridgman method in which KF was used as assisting flux and a large temperature gradient （70-90℃ /cm） of solid-liquid interface was adopted. Upconversion emissions at green -544 nm, red -657 and -751 nm were obtained under 980 nm laser diode excitation. The intensity at -544 nm was much stronger than those of -657 and -751 nm. The mechanisms of the upconversion emissions were investigated by studying the relationship between the upconversion intensity and pump power. The optimized Yb3＋ concentration was about 8.08moi% when Ho3＋ concentration was hold at about 1.0mol%. The results showed that Ho3＋/yb3＋ doped α-NaYF4 single crystal was a possible candidate upconversion material for the green solid-state laser.展开更多
Asteroid 469219 Kamo'oalewa,also named 2016 HO3,is a small-size fast-rotating near-Earth asteroid,which is a potential target for future explorations.Owing to its weak gravity and fast spin rate,the dynamics on th...Asteroid 469219 Kamo'oalewa,also named 2016 HO3,is a small-size fast-rotating near-Earth asteroid,which is a potential target for future explorations.Owing to its weak gravity and fast spin rate,the dynamics on the surface or in the vicinity of 2016 HO3 are significantly different from those of planets or other small bodies explored in previous missions.In this study,the geophysical and orbital environments of 2016 HO3 were investigated to facilitate a potential mission design.First,the geormnetric and geopotential topographies of 2016 HO3 were examined using difterent shape models.The liftoff and escape conditions on its fast-rotating surface were investigated.Then,the periodic orbits around 2016 HO3 were studied in the asteroid-fixed frame and the Sun-asteroid frame considering the solar radiation pressure.The stable regions of the terminator orbits were discussed using different parameters.Finally,the influence of the nonspherical shape on the terminator orbits was examined.The precise terminator orbits around a real shape model of 2016 HO3 were obtained and verified in the high-fidelity model.This study shows that the polar region of 2016 HO3 is the primary region for landing or sampling,and the terminator orbits are well suited for global mapping and measurements of 2016 HO3.The analysis and methods can also serve as references for the exploration of other small fast-rotating bodies.展开更多
This paper reports the simultaneous emissions around 1.53, 1.80, 2.10, 2.70 and 3.00 gm in Er3＋-Ho3＋ - Nd3＋/Tm3＋-codoped telluride glasses upon excitation of a conventional 808 nm laser diode. Both emission bands ...This paper reports the simultaneous emissions around 1.53, 1.80, 2.10, 2.70 and 3.00 gm in Er3＋-Ho3＋ - Nd3＋/Tm3＋-codoped telluride glasses upon excitation of a conventional 808 nm laser diode. Both emission bands of 1.53 and 2.70 gm were assigned to the transitions of 4113/2 -4115/2, 4111/2 -4113/2 of Er＋＋ ions, respectively, the emission near 1.80 gm was assigned to the transition ＊F4 -4H6 of Tm3＋ ions, and the emissions at 2.10 and 3.00 μm arose from the transitions of 5I7 -518, 5I6 -5I7 of Ho3＋ ions. The materials are promising for ultra-broad band amplified spontaneous emission optical sources at near and middle infrared region.展开更多
基金the National Natural Science Foundation of China(11874186)the Applied Basic Research Program of Yunnan Province(2017FB079)+1 种基金the Reserve Talents Project of Yunnan Province(2015HB013)the Scientific Research Foundation of the Education Department of Yunnan Province(2018JS452)。
文摘Exploring a new tuning way to facilely realize single-band red emission in trivalent rare-earth ions(RE3+) doped upconversion(UC) materials is still desirable.In this work,the intense single-band red emission is achieved by co-doping only Ho3+in the BiOCl:Er3+ under 1550 nm excitation.In the BiOCl layered host,co-doping Ho3+can further enhance the red emission and simultaneously suppress the green emission of Er3+,and thus obviously improve the red-to-green(R/G) ratio.It is found that Ho3+does not se rve as ene rgy trapping through the 5 I6 state as in traditional UC materials but acts as ET bridge(4 S3/2,2 H11/2(Er3+)→5 F4,5 S2(Ho3+)→4 F9/2(Er3+)).The tuning mechanism of Ho3+is discussed in detail and further confirms through a comparative experiment.Our research gives an unusual perspective to tune the UC behavior of Er3+through co-doping Ho3+,which might be inspiring for achievement of single-band red UC emission.
基金This work was supported by the National Natural Science Foundation of China （No.51472125, No.51272109） and K. C. Wong Magna Fund in Ningbo University.
文摘The Ho3＋/yb3＋ co-doped a-NaYF4 single crystal was grown successfully for the first time by a modified Bridgman method in which KF was used as assisting flux and a large temperature gradient （70-90℃ /cm） of solid-liquid interface was adopted. Upconversion emissions at green -544 nm, red -657 and -751 nm were obtained under 980 nm laser diode excitation. The intensity at -544 nm was much stronger than those of -657 and -751 nm. The mechanisms of the upconversion emissions were investigated by studying the relationship between the upconversion intensity and pump power. The optimized Yb3＋ concentration was about 8.08moi% when Ho3＋ concentration was hold at about 1.0mol%. The results showed that Ho3＋/yb3＋ doped α-NaYF4 single crystal was a possible candidate upconversion material for the green solid-state laser.
基金support from the National Natural Science Foundation of China(Grant Nos.12002028 and 51827806)Beijing Institute of Technology Research Fund Program for Young Scholars,China Postdoctoral Science Foundation funded project(Grant No.2019QT0038)Ann and H.J.Smead Aerospace Engineering Science Department,University of Colorado Boulder。
文摘Asteroid 469219 Kamo'oalewa,also named 2016 HO3,is a small-size fast-rotating near-Earth asteroid,which is a potential target for future explorations.Owing to its weak gravity and fast spin rate,the dynamics on the surface or in the vicinity of 2016 HO3 are significantly different from those of planets or other small bodies explored in previous missions.In this study,the geophysical and orbital environments of 2016 HO3 were investigated to facilitate a potential mission design.First,the geormnetric and geopotential topographies of 2016 HO3 were examined using difterent shape models.The liftoff and escape conditions on its fast-rotating surface were investigated.Then,the periodic orbits around 2016 HO3 were studied in the asteroid-fixed frame and the Sun-asteroid frame considering the solar radiation pressure.The stable regions of the terminator orbits were discussed using different parameters.Finally,the influence of the nonspherical shape on the terminator orbits was examined.The precise terminator orbits around a real shape model of 2016 HO3 were obtained and verified in the high-fidelity model.This study shows that the polar region of 2016 HO3 is the primary region for landing or sampling,and the terminator orbits are well suited for global mapping and measurements of 2016 HO3.The analysis and methods can also serve as references for the exploration of other small fast-rotating bodies.
文摘This paper reports the simultaneous emissions around 1.53, 1.80, 2.10, 2.70 and 3.00 gm in Er3＋-Ho3＋ - Nd3＋/Tm3＋-codoped telluride glasses upon excitation of a conventional 808 nm laser diode. Both emission bands of 1.53 and 2.70 gm were assigned to the transitions of 4113/2 -4115/2, 4111/2 -4113/2 of Er＋＋ ions, respectively, the emission near 1.80 gm was assigned to the transition ＊F4 -4H6 of Tm3＋ ions, and the emissions at 2.10 and 3.00 μm arose from the transitions of 5I7 -518, 5I6 -5I7 of Ho3＋ ions. The materials are promising for ultra-broad band amplified spontaneous emission optical sources at near and middle infrared region.
