The possible ways and progress of infrared or red laser pumped green and blue laser emissions from a single solid state material doped by rare earth ions are outlined. The green and blue lasers realized from infrared ...The possible ways and progress of infrared or red laser pumped green and blue laser emissions from a single solid state material doped by rare earth ions are outlined. The green and blue lasers realized from infrared laser pumped rare earth doped nonlinear laser crystals by means of self frequency conversion and from infrared laser pumped rare earth doped bulk, fiber and microsphere materials by means of frequency upconversion are introduced in detail. Other kinds of devices and methods are also compared. The typical nonlinear laser crystals such as YAl 3(BO 3) 4, GdAl 3(BO 3) 4, YCa 4O(BO 3) 3 , GdCa 4O(BO 3) 3, and the typical upconversion fluoride fibers are compared and analyzed. The major problems remaining to be solved and the developing trends in the area are also discussed.展开更多
AIM:To document the prognosis of laser treatment in patients with exudative age-related macular degeneration(AMD).· METHODS:Efficacy of the intervention was evaluated using a before-after method.· RESULTS:A ...AIM:To document the prognosis of laser treatment in patients with exudative age-related macular degeneration(AMD).· METHODS:Efficacy of the intervention was evaluated using a before-after method.· RESULTS:A total of 392 eyes of 341 patients with exudative AMD were examined.77.6% had choroideal neovascularisation(CNV).Before the use of indocyanine green(ICG) angiography,occult CNV was detected in only 1.8% of the eyes,but after the use of ICG angiography,this increased to 19.5%(P<0.001).Of the 349 eyes which were followed up,visual acuity had remained stable in 68.2% of the eyes.There was a statistically significant relationship between localisation of lesion and visual acuity changes on pre-and post-laser treatment(P<0.001).Also there was a statistically significant relationship between localisation of lesion and recurrence(P<0.05).The recurrence was less in subfoveal lesions than that in juxtafoveal and extrafoveal lesions.· CONCLUSION:ICG angiography is highly important in the treatment of occult CNV.展开更多
A novel method of codoping the Er^3＋, Yb^3＋, and Ho^3＋ ions in tellurite glasses is demonstrated to obtain a high efficiency of infrared-to-visible upconversion. Three intense emission bands observed in Er^3＋, Yb^...A novel method of codoping the Er^3＋, Yb^3＋, and Ho^3＋ ions in tellurite glasses is demonstrated to obtain a high efficiency of infrared-to-visible upconversion. Three intense emission bands observed in Er^3＋, Yb^3＋, and Ho^3＋ codoped tellurite glasses centred at 525, 547, and 657nm correspond to Er^3＋： ^2H11/2 -4 ^4I15/2, Er^3＋： ^4S3/2 →^4I15/2＋Ho^3＋： ^5S2（^5F4） → ^5Is, and Er^3＋： ^4Sa/2 → ^4I15/2＋Ho^3＋： ^5F5 → ^5Is transitions, respectively. No visible upconversion quenching phenomenon is observed when three rare-earth ions are codoped together in tellurite glasses. In contrast, the upconversion intensity of red and green emissions in Er^3＋, Yb^3＋, and Ho^3＋ codoped glasses is enhanced largely when compared with Er^3＋ /Yb^3＋-codoped glasses. The dependence of upconversion intensities on excitation power and the possible upconversion mechanisms are evaluated. The three emissions are based on two-photon absorption processes.展开更多
We propose and experimentally demonstrate a recorded 1-m bidirectional 20.231-Gbit/s tricolor R/G/B laser diode(LD) based visible-light communication(VLC) system supporting signal remodulation. In the signal remodulat...We propose and experimentally demonstrate a recorded 1-m bidirectional 20.231-Gbit/s tricolor R/G/B laser diode(LD) based visible-light communication(VLC) system supporting signal remodulation. In the signal remodulation system, an LD source is not needed at the client side. The client reuses the downstream signal sent from the central office(CO) and remodulates it to produce the upstream signal. As the LD sources are located at the CO, the laser wavelength and temperature managements at the cost-sensitive client side are not needed.This is the first demonstration, to our knowledge, of a >20 Gbit∕s data rate tricolor R/G/B VLC signal transmission supporting upstream remodulation.展开更多
The key for the development of high -density optical storage technology nowadays is to develop short wavelength (blue-green laser) recording media and devices. Based on the progress achieved in the key program of Nati...The key for the development of high -density optical storage technology nowadays is to develop short wavelength (blue-green laser) recording media and devices. Based on the progress achieved in the key program of National Natural Science Foundation of China "high-density optical storage materials using blue -green laser recording", the chemical composition, microstructure, storage performance and related mechanisms of some kinds of novel high density optical storage materials are presented in this paper. The research method and clew for super high -density optical storage materials and technologies are highlighted.展开更多
文摘The possible ways and progress of infrared or red laser pumped green and blue laser emissions from a single solid state material doped by rare earth ions are outlined. The green and blue lasers realized from infrared laser pumped rare earth doped nonlinear laser crystals by means of self frequency conversion and from infrared laser pumped rare earth doped bulk, fiber and microsphere materials by means of frequency upconversion are introduced in detail. Other kinds of devices and methods are also compared. The typical nonlinear laser crystals such as YAl 3(BO 3) 4, GdAl 3(BO 3) 4, YCa 4O(BO 3) 3 , GdCa 4O(BO 3) 3, and the typical upconversion fluoride fibers are compared and analyzed. The major problems remaining to be solved and the developing trends in the area are also discussed.
文摘AIM:To document the prognosis of laser treatment in patients with exudative age-related macular degeneration(AMD).· METHODS:Efficacy of the intervention was evaluated using a before-after method.· RESULTS:A total of 392 eyes of 341 patients with exudative AMD were examined.77.6% had choroideal neovascularisation(CNV).Before the use of indocyanine green(ICG) angiography,occult CNV was detected in only 1.8% of the eyes,but after the use of ICG angiography,this increased to 19.5%(P<0.001).Of the 349 eyes which were followed up,visual acuity had remained stable in 68.2% of the eyes.There was a statistically significant relationship between localisation of lesion and visual acuity changes on pre-and post-laser treatment(P<0.001).Also there was a statistically significant relationship between localisation of lesion and recurrence(P<0.05).The recurrence was less in subfoveal lesions than that in juxtafoveal and extrafoveal lesions.· CONCLUSION:ICG angiography is highly important in the treatment of occult CNV.
基金Supported by the Science and Technology Department of Zhejiang Province under Grant No 2006C21082, the Natural Science Foundation of Zhejiang Province under Grant No 601011.
文摘A novel method of codoping the Er^3＋, Yb^3＋, and Ho^3＋ ions in tellurite glasses is demonstrated to obtain a high efficiency of infrared-to-visible upconversion. Three intense emission bands observed in Er^3＋, Yb^3＋, and Ho^3＋ codoped tellurite glasses centred at 525, 547, and 657nm correspond to Er^3＋： ^2H11/2 -4 ^4I15/2, Er^3＋： ^4S3/2 →^4I15/2＋Ho^3＋： ^5S2（^5F4） → ^5Is, and Er^3＋： ^4Sa/2 → ^4I15/2＋Ho^3＋： ^5F5 → ^5Is transitions, respectively. No visible upconversion quenching phenomenon is observed when three rare-earth ions are codoped together in tellurite glasses. In contrast, the upconversion intensity of red and green emissions in Er^3＋, Yb^3＋, and Ho^3＋ codoped glasses is enhanced largely when compared with Er^3＋ /Yb^3＋-codoped glasses. The dependence of upconversion intensities on excitation power and the possible upconversion mechanisms are evaluated. The three emissions are based on two-photon absorption processes.
基金Ministry of Science and Technology,Taiwan(MOST)(MOST-106-2221-E-009-105-MY3)Aim for the Top University PlanMinistry of Education(MOE),Taiwan,China
文摘We propose and experimentally demonstrate a recorded 1-m bidirectional 20.231-Gbit/s tricolor R/G/B laser diode(LD) based visible-light communication(VLC) system supporting signal remodulation. In the signal remodulation system, an LD source is not needed at the client side. The client reuses the downstream signal sent from the central office(CO) and remodulates it to produce the upstream signal. As the LD sources are located at the CO, the laser wavelength and temperature managements at the cost-sensitive client side are not needed.This is the first demonstration, to our knowledge, of a >20 Gbit∕s data rate tricolor R/G/B VLC signal transmission supporting upstream remodulation.
文摘The key for the development of high -density optical storage technology nowadays is to develop short wavelength (blue-green laser) recording media and devices. Based on the progress achieved in the key program of National Natural Science Foundation of China "high-density optical storage materials using blue -green laser recording", the chemical composition, microstructure, storage performance and related mechanisms of some kinds of novel high density optical storage materials are presented in this paper. The research method and clew for super high -density optical storage materials and technologies are highlighted.
