Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward tra...Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward transfer function, which relates the laser output intensity to the pump modulations, is measured and analyzed. A custom two-path feedback system operating at different frequency bands is designed to adjust the pump current directly. The relative intensity noise is decreased by 20dB from 0.2 to 5kHz and over lOdB from 5 to lOkHz. The relaxation oscillation peak is suppressed by 22dB. In addition, a long term (24h) laser instability of less than 0.05% is achieved.展开更多
A method of fabricating selenium(Se) microwire is demonstrated.A multimaterial fiber with amorphous selenium(a-Se) core and multicomponent phosphate glass cladding is drawn by using a conventional optical fiber dr...A method of fabricating selenium(Se) microwire is demonstrated.A multimaterial fiber with amorphous selenium(a-Se) core and multicomponent phosphate glass cladding is drawn by using a conventional optical fiber drawing technique.Then the a-Se core of the fiber is crystallized by a post thermal process at 150 ℃.After the multicomponent phosphate glass cladding is stripped from the multimaterial fiber by marinating the fiber in HF acid solution,a crystalline selenium(c-Se)microwire with high uniformity and smooth surface is obtained.Based on microstructure measurements,the c-Se microwire is identified to consist of most hexagonal state particles and very few trigonal state whiskers.The good photoconduction property of c-Se microwire with high quality and longer continuous length makes it possible to apply to functional devices and arrays.展开更多
Effects of Nb_(2)O_(5)dopant on the radiation response of barium gallo-germanate(BGG)glass are studied mainly by electron paramagnetic resonance and absorption spectroscopy.Owing to the Nb^(5+)$Nb^(3+)interconversion ...Effects of Nb_(2)O_(5)dopant on the radiation response of barium gallo-germanate(BGG)glass are studied mainly by electron paramagnetic resonance and absorption spectroscopy.Owing to the Nb^(5+)$Nb^(3+)interconversion in doped samples,formations of Ge-related non-bridging oxygen hole center and Ge-related electron center defects after g-ray irradiation are inhibited.Thereby,Nb_(2)O_(5)dopant can enhance radiation resistance of BGG glass,and 1.0%Nb2O5 concentration is the best.展开更多
Energy transfer among the co-doped activators is an efficient route to achieve color-tunable emission in inorganic phosphors.Herein,photoluminescence tuning from blue to cyan has been achieved in the Lu2MgAl4 SiO12;Eu...Energy transfer among the co-doped activators is an efficient route to achieve color-tunable emission in inorganic phosphors.Herein,photoluminescence tuning from blue to cyan has been achieved in the Lu2MgAl4 SiO12;Eu^2+,Ce^3+phosphors by varying the Ce^3+concentration with a fixed Eu^2+content.With the further introduction of a Mn^2+-Si^4+couple into the host lattice,the emission color can be tuned to red through the energy transfer of Eu^2+and Mn^2+.The luminescence properties and the energy transfer mechanism were studied in detail.The energy transfer from Eu^2+to Ce^3+is certified as a dipolequadrupole interaction with the energy transfer efficiency of 41.4%and Eu^2+to Mn^2+belongs to a dipole-dipole interaction with the energy transfer efficiency of 94.3%.The results imply that this singlephased Lu2MgAl4 SiO12:Eu^2+,Ce^3+,Mn^2+phosphor has a potential prospect for application in near-UV chip pumped white light emitting diodes.展开更多
Encoding information in light polarization is of great importance in facilitating optical data storage(ODS)for information security and data storage capacity escalation.However,despite recent advances in nanophotonic ...Encoding information in light polarization is of great importance in facilitating optical data storage(ODS)for information security and data storage capacity escalation.However,despite recent advances in nanophotonic techniques vastly en-hancing the feasibility of applying polarization channels,the data fidelity in reconstructed bits has been constrained by severe crosstalks occurring between varied polarization angles during data recording and reading process,which gravely hindered the utilization of this technique in practice.In this paper,we demonstrate an ultra-low crosstalk polarization-en-coding multilayer ODS technique for high-fidelity data recording and retrieving by utilizing a nanofibre-based nanocom-posite film involving highly aligned gold nanorods(GNRs).With parallelizing the gold nanorods in the recording medium,the information carrier configuration minimizes miswriting and misreading possibilities for information input and output,respectively,compared with its randomly self-assembled counterparts.The enhanced data accuracy has significantly im-proved the bit recall fidelity that is quantified by a correlation coefficient higher than 0.99.It is anticipated that the demon-strated technique can facilitate the development of multiplexing ODS for a greener future.展开更多
A noise-sidebands-free and ultra-low relative intensity noise(RIN) 1.5 μm single-frequency fiber laser is demonstrated for the first time to our best knowledge. Utilizing a self-injection locking framework and a boos...A noise-sidebands-free and ultra-low relative intensity noise(RIN) 1.5 μm single-frequency fiber laser is demonstrated for the first time to our best knowledge. Utilizing a self-injection locking framework and a booster optical amplifier, the noise sidebands with relative amplitudes as high as 20 dB are completely suppressed.The RIN is remarkably reduced by more than 64 dB at the relaxation oscillation peak to retain below-150 dB∕Hz in a frequency range from 75 kHz to 50 MHz, while the quantum noise limit is -152.9 d B∕Hz.Furthermore, a laser linewidth narrower than 600 Hz, a polarization-extinction ratio of more than 23 dB, and an optical signal-to-noise ratio of more than 73 dB are acquired simultaneously. This noise-sidebands-free and ultralow-RIN single-frequency fiber laser is highly competitive in advanced coherent light detection fields including coherent Doppler wind lidar, high-speed coherent optical communication, and precise absolute distance coherent measurement.展开更多
A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3+-doped germanate glass fiber. Over 100...A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3+-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 195Ohm are achieved. The measured relative intensity noise is less than -135dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72dB, and the laser linewidth is less than 6kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.展开更多
In this paper,a technique combining the cascaded energy-transfer pumping(CEP)method and master-oscillator power-amplifier(MOPA)configuration is proposed for power scaling of 1.6-μm-band single-frequency fiber lasers(...In this paper,a technique combining the cascaded energy-transfer pumping(CEP)method and master-oscillator power-amplifier(MOPA)configuration is proposed for power scaling of 1.6-μm-band single-frequency fiber lasers(SFFLs),where the Er^(3+)ion has a limited gain.The CEP technique is fulfilled by coupling a primary signal light at 1.6μm and a C-band auxiliary laser.The numerical model of the fiber amplifier with the CEP technique reveals that the energy transfer process involves the pump competition and the in-band particle transition between the signal and auxiliary lights.Moreover,for the signal emission,the population density in the upper level is enhanced,and the effective population inversion is achieved thanks to the CEP.A single-frequency MOPA laser at 1603 nm with an output power of 52.6 W and an improved slope efficiency of 30.4%is experimentally obtained through the CEP technique.Besides,a laser linewidth of 5.2 k Hz and a signal-to-auxiliary laser ratio of 60.7 d B are obtained at the maximum output power.The proposed technique is anticipated to be promising for increasing the slope efficiency and power scaling for fiber lasers operating at L band.展开更多
Transverse mode instability(TMI)has become the major limitation for power scaling of fiber lasers with nearly diffraction-limited beam quality.Compared with a co-pumped fiber laser,a counter-pumped fiber laser reveals...Transverse mode instability(TMI)has become the major limitation for power scaling of fiber lasers with nearly diffraction-limited beam quality.Compared with a co-pumped fiber laser,a counter-pumped fiber laser reveals TMI threshold enhancement through a semi-analytical model calculation.We demonstrated a 2 kW high-power counter-pumped all-fiberized laser without observation of TMI.Compared with the co-pumped scheme,the TMI threshold is enhanced at least 50%in counter-pumped scheme,moreover,stimulated Raman scattering and four-wave mixing are suppressed simultaneously.展开更多
A new way to improve the 1.53μm emission in Er3+/Yb3+ co-doped multicomponent phosphate glass was demonstrated by introducing silver nanoparticles (NPs) in rare-earth doped glass. The existence of Ag NPs was conf...A new way to improve the 1.53μm emission in Er3+/Yb3+ co-doped multicomponent phosphate glass was demonstrated by introducing silver nanoparticles (NPs) in rare-earth doped glass. The existence of Ag NPs was confirmed by absorption spectra and transmission electron microscopy (TEM) measurements. The homogeneous distribution of silver NPs could be observed by the TEM images. UV-Vis-NIR absorption spectra revealed that the surface plasmon band was centered at about 420 nm. The photoluminescence spectra of glass samples were used to investigate the effect of silver NPs on the fluorescence properties of Er3+. Efficient 1.53μm emis-sion was obtained in prepared samples when pumped at 980 nm laser diode (LD). The 1.53μm emission intensity could be enhanced 87% by doping 2 mol.% AgCl due to the increased localized field effect in the vicinity of NPs and the possible energy transfer from silver NPs to Er3+ions. Our present work may point out one way to enhance the gain coefficient of Er3+/Yb3+ co-doped glass fiber.展开更多
Phosphor-converted white light-emitting diode(LED) lighting has gained tremendous achievements since the invention of the InGaN blue LED by Nakamura et al., who won the Nobel Physics Prize in 2014.By far, a significan...Phosphor-converted white light-emitting diode(LED) lighting has gained tremendous achievements since the invention of the InGaN blue LED by Nakamura et al., who won the Nobel Physics Prize in 2014.By far, a significant challenge comes from the thermal quenching(TQ) behavior of the present LED phosphors during the high-power LED operation or the updated laser lighting. But systematic research or review on the luminescence quenching character and/or how to realize thermally stable luminescence are lacking. Since TQ is an inherent property of phosphors, it can be diminished by different approaches.This review proceeds from the mechanism of TQ, summarizes previous researches on improving the thermal stability of LED phosphors and also discusses future research opportunities in this field. The developments of the phosphors with properties of high luminance and thermal stability, as well as the improved strategies involved,will benefit the basic researches and applications in high power lighting or high-luminance laser lighting.展开更多
基金Supported by the National High-Technology Research and Development Program of China under Grant Nos 2013AA031502 and 2014AA041902the National Natural Science Foundation of China under Grant Nos 11174085,51132004,and 51302086+3 种基金the Guangdong Natural Science Foundation under Grant Nos S2011030001349 and S20120011380the China National Funds for Distinguished Young Scientists under Grant No 61325024the Science and Technology Project of Guangdong Province under Grant No 2013B090500028the’Cross and Cooperative’Science and Technology Innovation Team Project of Chinese Academy of Sciences under Grant No 2012-119
文摘Effective multiple optoelectronic feedback circuits for simultaneously suppressing low-frequency and relaxation oscillation intensity noise in a single-frequency phosphate fiber laser are demonstrated. The forward transfer function, which relates the laser output intensity to the pump modulations, is measured and analyzed. A custom two-path feedback system operating at different frequency bands is designed to adjust the pump current directly. The relative intensity noise is decreased by 20dB from 0.2 to 5kHz and over lOdB from 5 to lOkHz. The relaxation oscillation peak is suppressed by 22dB. In addition, a long term (24h) laser instability of less than 0.05% is achieved.
基金Project supported by the National Natural Science Foundation for Distinguished Young Scientists,China(Grant No.61325024)the High-Level Personnel Special Support Program of Guangdong Province,China(Grant No.2014TX01C087)+3 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.2015ZP019)the National High Technology and Development Program of China(Grant Nos.2013AA031502 and 2014AA041902)the National Natural Science Foundation of China(Grant Nos.51472088,61535014,and 51302086)the Fund of Guangdong Provincial Cooperation of Producing,Studying and Researching,China(Grant No.2012B091100140)
文摘A method of fabricating selenium(Se) microwire is demonstrated.A multimaterial fiber with amorphous selenium(a-Se) core and multicomponent phosphate glass cladding is drawn by using a conventional optical fiber drawing technique.Then the a-Se core of the fiber is crystallized by a post thermal process at 150 ℃.After the multicomponent phosphate glass cladding is stripped from the multimaterial fiber by marinating the fiber in HF acid solution,a crystalline selenium(c-Se)microwire with high uniformity and smooth surface is obtained.Based on microstructure measurements,the c-Se microwire is identified to consist of most hexagonal state particles and very few trigonal state whiskers.The good photoconduction property of c-Se microwire with high quality and longer continuous length makes it possible to apply to functional devices and arrays.
基金supported by China National Funds for Guangdong Key Research and Development Program(Grant No.2018B090904001)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(Grant No.2017BT01X137)+2 种基金Key Laboratory of Laser Device Technology Foundation of China Ordnance Industry Group Co.(Grant No.KLLDT202010)the Key R&D Program of Guangzhou(Grant No.202007020003)the National Natural Science Foundation of China(Grant No.52002131)。
文摘Effects of Nb_(2)O_(5)dopant on the radiation response of barium gallo-germanate(BGG)glass are studied mainly by electron paramagnetic resonance and absorption spectroscopy.Owing to the Nb^(5+)$Nb^(3+)interconversion in doped samples,formations of Ge-related non-bridging oxygen hole center and Ge-related electron center defects after g-ray irradiation are inhibited.Thereby,Nb_(2)O_(5)dopant can enhance radiation resistance of BGG glass,and 1.0%Nb2O5 concentration is the best.
基金Project supported by the National Natural Science Foundation of China(51972118,51722202,51572023)Natural Science Foundation of Beijing(2172036)Fundamental Research Funds for the Central Universities(FRF-TP-18-002C1)。
文摘Energy transfer among the co-doped activators is an efficient route to achieve color-tunable emission in inorganic phosphors.Herein,photoluminescence tuning from blue to cyan has been achieved in the Lu2MgAl4 SiO12;Eu^2+,Ce^3+phosphors by varying the Ce^3+concentration with a fixed Eu^2+content.With the further introduction of a Mn^2+-Si^4+couple into the host lattice,the emission color can be tuned to red through the energy transfer of Eu^2+and Mn^2+.The luminescence properties and the energy transfer mechanism were studied in detail.The energy transfer from Eu^2+to Ce^3+is certified as a dipolequadrupole interaction with the energy transfer efficiency of 41.4%and Eu^2+to Mn^2+belongs to a dipole-dipole interaction with the energy transfer efficiency of 94.3%.The results imply that this singlephased Lu2MgAl4 SiO12:Eu^2+,Ce^3+,Mn^2+phosphor has a potential prospect for application in near-UV chip pumped white light emitting diodes.
基金financial supports from the National Natural Science Foundation of China(Grant Nos.62174073,61875073,11674130,91750110 and 61522504)the National Key R&D Program of China(Grant No.2018YFB1107200)+3 种基金the Guangdong Provincial Innovation and Entrepren-eurship Project(Grant No.2016ZT06D081)the Natural Science Founda-tion of Guangdong Province,China(Grant Nos.2016A030306016 and 2016TQ03X981)the Pearl River Nova Program of Guangzhou(Grant No.201806010040)the Technology Innovation and Development Plan of Yantai(Grant No.2020XDRH095).
文摘Encoding information in light polarization is of great importance in facilitating optical data storage(ODS)for information security and data storage capacity escalation.However,despite recent advances in nanophotonic techniques vastly en-hancing the feasibility of applying polarization channels,the data fidelity in reconstructed bits has been constrained by severe crosstalks occurring between varied polarization angles during data recording and reading process,which gravely hindered the utilization of this technique in practice.In this paper,we demonstrate an ultra-low crosstalk polarization-en-coding multilayer ODS technique for high-fidelity data recording and retrieving by utilizing a nanofibre-based nanocom-posite film involving highly aligned gold nanorods(GNRs).With parallelizing the gold nanorods in the recording medium,the information carrier configuration minimizes miswriting and misreading possibilities for information input and output,respectively,compared with its randomly self-assembled counterparts.The enhanced data accuracy has significantly im-proved the bit recall fidelity that is quantified by a correlation coefficient higher than 0.99.It is anticipated that the demon-strated technique can facilitate the development of multiplexing ODS for a greener future.
基金National Natural Science Foundation of China(NSFC)(11674103,61535014,61635004)Major Program of the National Natural Science Foundation of China(61790582)+3 种基金Fundamental Research Funds for Central Universities(2015ZM091,2017BQ002)China National Funds for Distinguished Young Scientists(61325024)Natural Science Foundation of Guangdong Province(2016A030310410,2017A030310007)Science and Technology Project of Guangdong(2014B050505007,2015B090926010,2016B090925004,2017B090911005)
文摘A noise-sidebands-free and ultra-low relative intensity noise(RIN) 1.5 μm single-frequency fiber laser is demonstrated for the first time to our best knowledge. Utilizing a self-injection locking framework and a booster optical amplifier, the noise sidebands with relative amplitudes as high as 20 dB are completely suppressed.The RIN is remarkably reduced by more than 64 dB at the relaxation oscillation peak to retain below-150 dB∕Hz in a frequency range from 75 kHz to 50 MHz, while the quantum noise limit is -152.9 d B∕Hz.Furthermore, a laser linewidth narrower than 600 Hz, a polarization-extinction ratio of more than 23 dB, and an optical signal-to-noise ratio of more than 73 dB are acquired simultaneously. This noise-sidebands-free and ultralow-RIN single-frequency fiber laser is highly competitive in advanced coherent light detection fields including coherent Doppler wind lidar, high-speed coherent optical communication, and precise absolute distance coherent measurement.
基金Supported by the National High-Technology Research and Development Program of China under Grant Nos 2013AA031502 and 2014AA041902the National Natural Science Foundation of China under Grant Nos 11174085,51132004,and 51302086+3 种基金the Natural Science Foundation of Guangdong Province under Grant Nos S2011030001349 and S20120011380the China National Funds for Distinguished Young Scientists under Grant No 61325024the Science and Technology Project of Guangdong Province under Grant No 2013B090500028the ’Cross and Cooperative’ Science and Technology Innovation Team Project of Chinese Academy of Sciences under Grant No 2012-119
文摘A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3+-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 195Ohm are achieved. The measured relative intensity noise is less than -135dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72dB, and the laser linewidth is less than 6kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.
基金National Key Research and Development Program of China(2017YFF0104602)Major Program of the National Natural Science Foundation of China(61790582)+4 种基金NSFC(11674103,51772101,61535014,61635004)Guangdong Key Research and Development Program(2018B090904001,2018B090904003)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X137)Natural Science Foundation of Guangdong Province(2016A030310410,2017A030310007)Science and Technology Project of Guangdong(2016B090925004,2017B090911005,201804020028)。
文摘In this paper,a technique combining the cascaded energy-transfer pumping(CEP)method and master-oscillator power-amplifier(MOPA)configuration is proposed for power scaling of 1.6-μm-band single-frequency fiber lasers(SFFLs),where the Er^(3+)ion has a limited gain.The CEP technique is fulfilled by coupling a primary signal light at 1.6μm and a C-band auxiliary laser.The numerical model of the fiber amplifier with the CEP technique reveals that the energy transfer process involves the pump competition and the in-band particle transition between the signal and auxiliary lights.Moreover,for the signal emission,the population density in the upper level is enhanced,and the effective population inversion is achieved thanks to the CEP.A single-frequency MOPA laser at 1603 nm with an output power of 52.6 W and an improved slope efficiency of 30.4%is experimentally obtained through the CEP technique.Besides,a laser linewidth of 5.2 k Hz and a signal-to-auxiliary laser ratio of 60.7 d B are obtained at the maximum output power.The proposed technique is anticipated to be promising for increasing the slope efficiency and power scaling for fiber lasers operating at L band.
基金National Natural Science Foundation of China(NSFC)(11174085,11404305,11474257,51132004,51302086)China State 863 Hi-tech Program(2013AA031502,2014AA041902)+1 种基金Guangdong Natural Science Foundation(S20120011380)China National Funds for Distinguished Young Scientists(61325024)
文摘Transverse mode instability(TMI)has become the major limitation for power scaling of fiber lasers with nearly diffraction-limited beam quality.Compared with a co-pumped fiber laser,a counter-pumped fiber laser reveals TMI threshold enhancement through a semi-analytical model calculation.We demonstrated a 2 kW high-power counter-pumped all-fiberized laser without observation of TMI.Compared with the co-pumped scheme,the TMI threshold is enhanced at least 50%in counter-pumped scheme,moreover,stimulated Raman scattering and four-wave mixing are suppressed simultaneously.
基金Project supported by the High-level Personnel Special Support Program of Guangdong Province(2014TX01C087)China National Funds for Distinguished Young Scientists(61325024)+2 种基金Fundamental Research Funds for the Central Universities(2015ZP019)the Science and Technology Project of Guangdong(2015B090926010)Hi-tech Research and Development Program of China(2013AA031502)
文摘A new way to improve the 1.53μm emission in Er3+/Yb3+ co-doped multicomponent phosphate glass was demonstrated by introducing silver nanoparticles (NPs) in rare-earth doped glass. The existence of Ag NPs was confirmed by absorption spectra and transmission electron microscopy (TEM) measurements. The homogeneous distribution of silver NPs could be observed by the TEM images. UV-Vis-NIR absorption spectra revealed that the surface plasmon band was centered at about 420 nm. The photoluminescence spectra of glass samples were used to investigate the effect of silver NPs on the fluorescence properties of Er3+. Efficient 1.53μm emis-sion was obtained in prepared samples when pumped at 980 nm laser diode (LD). The 1.53μm emission intensity could be enhanced 87% by doping 2 mol.% AgCl due to the increased localized field effect in the vicinity of NPs and the possible energy transfer from silver NPs to Er3+ions. Our present work may point out one way to enhance the gain coefficient of Er3+/Yb3+ co-doped glass fiber.
基金Project supported by the National Natural Science Foundation of China(51722202,91622125,51572023)Natural Science Foundation of Beijing,China(2172036)
文摘Phosphor-converted white light-emitting diode(LED) lighting has gained tremendous achievements since the invention of the InGaN blue LED by Nakamura et al., who won the Nobel Physics Prize in 2014.By far, a significant challenge comes from the thermal quenching(TQ) behavior of the present LED phosphors during the high-power LED operation or the updated laser lighting. But systematic research or review on the luminescence quenching character and/or how to realize thermally stable luminescence are lacking. Since TQ is an inherent property of phosphors, it can be diminished by different approaches.This review proceeds from the mechanism of TQ, summarizes previous researches on improving the thermal stability of LED phosphors and also discusses future research opportunities in this field. The developments of the phosphors with properties of high luminance and thermal stability, as well as the improved strategies involved,will benefit the basic researches and applications in high power lighting or high-luminance laser lighting.
基金supported by the National Natural Science Foundation of China(U1609219,51632008,61721005,51432001and 51772268)Zhejiang Provincial Natural Science Foundation(LD18E020001)