Realizing a high color rendering index(CRI)in Ce:LuAG transparent ceramics(TCs)with desired thermal stability is essential to their applications in white LEDs/LDs as color converters.In this study,based on the scheme ...Realizing a high color rendering index(CRI)in Ce:LuAG transparent ceramics(TCs)with desired thermal stability is essential to their applications in white LEDs/LDs as color converters.In this study,based on the scheme of configuring the red component by Cr^(3+) doping,an efficient spectral regulation was realized in Ce,Cr:LuAG TCs.A unilateral shift phenomenon could be observed in both photoluminescence(PL)and photoluminescence excitation(PLE)spectra of TCs.By constructing TC-based white LED/LD devices in a remote excitation mode,luminescence properties of Ce,Cr:LuAG TCs were systematically investigated.The CRI values of Ce:LuAG TC based white LEDs could be increased by a magnitude of 46.2%.Particularly,by combining the as fabricated Ce,Cr:LuAG TCs with a 0.5 at% Ce:YAG TC,surprising CRI values of 88 and 85.5 were obtained in TC based white LEDs and LDs,respectively.Therefore,Ce,Cr:LuAG TC is a highly promising color convertor for high-power white LEDs/LDs applied in general lighting and displaying.展开更多
The Cr4+-doped yttrium aluminum garnet(Cr4+:YAG) saturable absorber, a new generation of passively Q-switched solid-state laser material, faces a significant obstacle of low conversion rate of chromium from trivalent ...The Cr4+-doped yttrium aluminum garnet(Cr4+:YAG) saturable absorber, a new generation of passively Q-switched solid-state laser material, faces a significant obstacle of low conversion rate of chromium from trivalent to tetravalent, degrading efficiency in a passively Q-switched laser. In this paper, highly transparent Cr4+:YAG ceramics were fabricated and committed to compare the laser performance with Cr4+:YAG crystals on a 1 μm passively Q-switched laser. Thanks to the grain boundary effect, the Cr4+conversion efficiency of 0.05 at.% Cr4+:YAG transparent ceramics coated with high transparency(HT) films(T = 86.46% at 1064 nm)was nine times higher than that of 0.1 at.% Cr4+:YAG single crystals coated with HT films(T = 84.00% at1064 nm). Differing from the counterpart Cr4+:YAG crystals, no absorption saturation tendency was observed for the 0.05 at.% Cr:YAG ceramics when the pump power exceeded ~1900 mW. Furthermore, the repetition frequency reached 217 kHz for 0.05 at.% Cr:YAG ceramics, which was a three-fold factor increase from that of the corresponding single crystal. The advantages of transparent ceramics over single crystals were proved through laser performance for the first time, to the best of our knowledge. This study also provided compelling evidence for replacing single crystals with ceramics for ultrafast dynamics.展开更多
基金the National Natural Science Foundation of China(61975070,51902143,61971207,and 61775088)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)+6 种基金Key Research and Development Project of Jiangsu Province(BE2018062,BE2019033)Natural Science foundation of Jiangsu Province(BK20191467)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX20_2336)International S&T Cooperation Program of Jiangsu Province(BZ2019063,BZ2020045,and BZ2020030)Natural Science Foundation of the Jiangsu Higher Education Institutes of China(19KJB43001&20KJA430003)Special Project for Technology Innovation of Xuzhou City(KC19250,KC20201,and KC20244)Open Project of State Key Laboratory of Advanced Materials and Electronic Components(FHR-JS-202011017).
文摘Realizing a high color rendering index(CRI)in Ce:LuAG transparent ceramics(TCs)with desired thermal stability is essential to their applications in white LEDs/LDs as color converters.In this study,based on the scheme of configuring the red component by Cr^(3+) doping,an efficient spectral regulation was realized in Ce,Cr:LuAG TCs.A unilateral shift phenomenon could be observed in both photoluminescence(PL)and photoluminescence excitation(PLE)spectra of TCs.By constructing TC-based white LED/LD devices in a remote excitation mode,luminescence properties of Ce,Cr:LuAG TCs were systematically investigated.The CRI values of Ce:LuAG TC based white LEDs could be increased by a magnitude of 46.2%.Particularly,by combining the as fabricated Ce,Cr:LuAG TCs with a 0.5 at% Ce:YAG TC,surprising CRI values of 88 and 85.5 were obtained in TC based white LEDs and LDs,respectively.Therefore,Ce,Cr:LuAG TC is a highly promising color convertor for high-power white LEDs/LDs applied in general lighting and displaying.
基金National Natural Science Foundation of China(NSFC)(51402133,51802142,61603160,61775088)Postgraduate Research Practice Innovation Program of Jiangsu Province(KYCX18_2096,KYCX18_2097,KYCX18_2098,KYCX18_2099)+2 种基金Special Project for Technology Innovation of Xuzhou City(KC16GZ014,KC16HQ236,KC16HQ237)Priority Academic Program Development of Jiangsu Higher Education Institutions(GRCK2017042411005977)Key Research and Development Project of Jiangsu Province(BE2018062,BE2019112)
文摘The Cr4+-doped yttrium aluminum garnet(Cr4+:YAG) saturable absorber, a new generation of passively Q-switched solid-state laser material, faces a significant obstacle of low conversion rate of chromium from trivalent to tetravalent, degrading efficiency in a passively Q-switched laser. In this paper, highly transparent Cr4+:YAG ceramics were fabricated and committed to compare the laser performance with Cr4+:YAG crystals on a 1 μm passively Q-switched laser. Thanks to the grain boundary effect, the Cr4+conversion efficiency of 0.05 at.% Cr4+:YAG transparent ceramics coated with high transparency(HT) films(T = 86.46% at 1064 nm)was nine times higher than that of 0.1 at.% Cr4+:YAG single crystals coated with HT films(T = 84.00% at1064 nm). Differing from the counterpart Cr4+:YAG crystals, no absorption saturation tendency was observed for the 0.05 at.% Cr:YAG ceramics when the pump power exceeded ~1900 mW. Furthermore, the repetition frequency reached 217 kHz for 0.05 at.% Cr:YAG ceramics, which was a three-fold factor increase from that of the corresponding single crystal. The advantages of transparent ceramics over single crystals were proved through laser performance for the first time, to the best of our knowledge. This study also provided compelling evidence for replacing single crystals with ceramics for ultrafast dynamics.
