The green and red up-conversion emissions centred at about 534, 549 and 663 nm of wavelength, corresponding respectively to the ^2H11/2 → ^4I15/2, ^4S3/2 → ^4I15/2 and ^4F9/2 → ^4I15/2 transitions of Er^3+ ions, h...The green and red up-conversion emissions centred at about 534, 549 and 663 nm of wavelength, corresponding respectively to the ^2H11/2 → ^4I15/2, ^4S3/2 → ^4I15/2 and ^4F9/2 → ^4I15/2 transitions of Er^3+ ions, have been observed for the Er^3+-doped silicate glass excited by a 978 nm semiconductor laser beam. Excitation power dependent behaviour of the up-conversion emission intensity indicates that a two-photon absorption up-conversion process is responsible for the green and red up-conversion emissions. The temperature dependence of the green up-conversion emissions is also studied in a temperature range of 296-673 K, which shows that Er^3+-doped silicate glass can be used as a sensor in high-temperature measurement.展开更多
The Er^(3+)-doped TeO_2-WO_3-ZnO-ZnF_2(TWZOF) glasses were prepared. The absorption spectra, 1.5 μm emission spectra and fluorescence lifetimes of Er^(3+), excited at 970 nm, were measured. The J-O parameters Ω_ t (...The Er^(3+)-doped TeO_2-WO_3-ZnO-ZnF_2(TWZOF) glasses were prepared. The absorption spectra, 1.5 μm emission spectra and fluorescence lifetimes of Er^(3+), excited at 970 nm, were measured. The J-O parameters Ω_ t (t =2, 4, 6), absorption and emission cross-sections were calculated. The dependence of the 1.5 μm emission intensity, fluorescence lifetime and bandwidth of the Er^(3+) emission upon the contents of ZnF_2 in glass were investigated. In TWZOF glass, Er^(3+) ions had a broad emission profile around 1.5 μm with the maximum FWHM of 83 nm. With the increasing of the content of ZnF_2, the emission intensity at peak wavelength and the fluorescence lifetime of Er^(3+) at 1.5 μm increase.展开更多
A simple three-level system is proposed to produce high index of refraction with zero absorption in an Er^3+-doped yttrium aluminium garnet (YAG) crystal, which is achieved for a probe field between the excited sta...A simple three-level system is proposed to produce high index of refraction with zero absorption in an Er^3+-doped yttrium aluminium garnet (YAG) crystal, which is achieved for a probe field between the excited state 4I13/2 and ground state 4I15/2 by adjusting a strong coherent driving field between the upper excited state 4I11/2 and 4I15/2. It is found that the changes of the frequency of the coherent driving field and the concentration of Er^3+ ions in the YAG crystal can maximize the index of refraction accompanied by vanishing absorption. This result could be useful for the dispersion compensation in fibre communication, laser particle acceleration, high precision magnetometry and so on.展开更多
Ce3+-doped Mn-Zn ferrite fibers were successfully prepared by the organic gel-thermal decomposition method from metal salts and citric acid. The composition,structure,and magnetic properties of these ferrite fibers we...Ce3+-doped Mn-Zn ferrite fibers were successfully prepared by the organic gel-thermal decomposition method from metal salts and citric acid. The composition,structure,and magnetic properties of these ferrite fibers were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),and vibrating sample magnetometer (VSM). The results show that Mn0.2Zn0.8Fe2-xCexO4 (x = 0-0.04) fibers are featured with an average grain size of 11.6-12.7 nm,with diameters ranging between 1.0 to 3.5 μm and a high ...展开更多
Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target produc...Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target products were characterized by thermogravimetric analyzer,X-ray diffrotometer,fourier transform infrared spectrometer,scanning electron microscope,spectrophotometer and infrared emissivity tester,and the effects of Er^(3+)doping on its infrared and laser emissivity were studied.At the same time,the Sn_(1−x)Er_(x)O_(2)(x=0%,16%)doping models were constructed based on the first principles of density functional theory,and the related optoelectronic properties such as their energy band structure,density of states,reflectivity and dielectric constant were analyzed,and further explained the mechanism of Er^(3+)doping on SnO_(2)infrared emissivity and laser absorption from the point of electronic structure.The results showed that after calcination at 600℃,single rutile type SnO_(2)was formed,and the crystal structure was not changed by doping Er^(3+).The calcined products showed good fiber morphology,and the average fiber diameter was 402 nm.The infrared emissivity and resistivity of the samples both decreased first and then increased with the increase of Er^(3+)doping amount.When x=16%,the infrared emis-sivity of the sample was at least 0.71;and Er^(3+)doping can effectively reduce the reflectivity of SnO_(2)at 1.06μm and 1.55μm,when x=16%,its reflectivity at 1.06μm and 1.55μm are 50.5%and 40%,respectively,when x=24%,the reflectivity at 1.06μm and 1.55μm wavelengths are 47.3%and 42.1%,respectively.At the same time,the change of carrier concentration and electron transition before and after Er^(3+)doping were described by first-principle calculation,and the regulation mechanism of infrared emissivity and laser reflectivity was explained.This study provides a certain experimental and theoretical basis for the development of a single-type,light-weight and easily prepared infrared and laser compatible-stealth material.展开更多
The .Er<sup>3+</sup>-Yb<sup>3+</sup>-doped fiber has a broadened absorption spectrum, which means the pumping sources can work efficiently from 810 to 1100nm. Among them 980nm is the maximum.ab...The .Er<sup>3+</sup>-Yb<sup>3+</sup>-doped fiber has a broadened absorption spectrum, which means the pumping sources can work efficiently from 810 to 1100nm. Among them 980nm is the maximum.absorption (10 dB/km) wavelength. By energy transferring and multiphoton process, the visible and ultraviolet radiation occurs when the Er<sup>3+</sup>-Yb<sup>3+</sup>-doped fiber is pumped by the laser at 980-nm band. Further researches on the mechanism of the fluorescence of Er<sup>3+</sup>-Yb<sup>3+</sup>-doped silica fiber pumped by Ti: A1<sub>2</sub>O<sub>3</sub> tunable laser at 980-nm band are helpful展开更多
Green semiconductor lasers are still undeveloped,so high-power green lasers have heavily relied on nonlinear frequency conversion of near-infrared lasers,precluding compact and low-cost green laser systems.Here,we rep...Green semiconductor lasers are still undeveloped,so high-power green lasers have heavily relied on nonlinear frequency conversion of near-infrared lasers,precluding compact and low-cost green laser systems.Here,we report the first Watt-level all-fiber CW Pr3t-doped laser operating directly in the green spectral region,addressing the aforementioned difficulties.The compact all-fiber laser consists of a double-clad Pr3t-doped fluoride fiber,two homemade fiber dichroic mirrors at visible wavelengths,and a 443-nm fiber-pigtailed pump source.Benefitting from>10 MW∕cm2 high damage intensity of our designed fiber dielectric mirror,the green laser can stably deliver 3.62-W of continuous-wave power at∼521 nm with a slope efficiency of 20.9%.To the best of our knowledge,this is the largest output power directly from green fiber lasers,which is one order higher than previously reported.Moreover,these green all-fiber laser designs are optimized by using experiments and numerical simulations.Numerical results are in excellent agreement with our experimental results and show that the optimal gain fiber length,output mirror reflectivity,and doping level should be considered to obtain higher power and efficiency.This work may pave a path toward compact high-power green all-fiber lasers for applications in biomedicine,laser display,underwater detection,and spectroscopy.展开更多
Based on the host of tellurite glasses, the glass formation, preform manufacture, and fiber fabrication are described. The characterization of amplified spontaneous emission (ASE) from this newly fabricated single-mod...Based on the host of tellurite glasses, the glass formation, preform manufacture, and fiber fabrication are described. The characterization of amplified spontaneous emission (ASE) from this newly fabricated single-mode Er3+-doped tellurite fibers is also presented. When pumped at 980 nm, a very broad erbium ASE around 1.53 μm was observed. The variations of ASE with fiber length and pumping power are measured and discussed. The output of 2 mW from Er3+-doped tellurite fiber ASE source was obtained under the pump power of 660 mW.展开更多
We report on the investigation of intermode beating mode-locked(IBML)pulse generation in a simple all-fiber Tm^3+-doped double clad fiber laser(TDFL).This IBML TDFL is implemented by matching longitudinal-mode frequen...We report on the investigation of intermode beating mode-locked(IBML)pulse generation in a simple all-fiber Tm^3+-doped double clad fiber laser(TDFL).This IBML TDFL is implemented by matching longitudinal-mode frequency between 793 nm laser and TDFL without extra mode locker.The central wavelength of 1983 nm,the fundamental pulse frequency of 9.6 MHz and the signal-to-noise ratio(SNR)of>50 dB are achieved in this IBML TDFL.With laser cavity optimization,the IBML TDFL can finally generate an average output power of 1.03 W with corresponding pulse energy of 107 nJ.These results can provide an easily accessible way to develop compact large-energy,highpower TDFLs.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 60477023)the Natural Science Foundation of Science and Technology Commission of Liaoning Province, China (Grant No 20062137)
文摘The green and red up-conversion emissions centred at about 534, 549 and 663 nm of wavelength, corresponding respectively to the ^2H11/2 → ^4I15/2, ^4S3/2 → ^4I15/2 and ^4F9/2 → ^4I15/2 transitions of Er^3+ ions, have been observed for the Er^3+-doped silicate glass excited by a 978 nm semiconductor laser beam. Excitation power dependent behaviour of the up-conversion emission intensity indicates that a two-photon absorption up-conversion process is responsible for the green and red up-conversion emissions. The temperature dependence of the green up-conversion emissions is also studied in a temperature range of 296-673 K, which shows that Er^3+-doped silicate glass can be used as a sensor in high-temperature measurement.
文摘The Er^(3+)-doped TeO_2-WO_3-ZnO-ZnF_2(TWZOF) glasses were prepared. The absorption spectra, 1.5 μm emission spectra and fluorescence lifetimes of Er^(3+), excited at 970 nm, were measured. The J-O parameters Ω_ t (t =2, 4, 6), absorption and emission cross-sections were calculated. The dependence of the 1.5 μm emission intensity, fluorescence lifetime and bandwidth of the Er^(3+) emission upon the contents of ZnF_2 in glass were investigated. In TWZOF glass, Er^(3+) ions had a broad emission profile around 1.5 μm with the maximum FWHM of 83 nm. With the increasing of the content of ZnF_2, the emission intensity at peak wavelength and the fluorescence lifetime of Er^(3+) at 1.5 μm increase.
基金Project supported by the National Natural Science Foundation of China (Grant No 10334010).
文摘A simple three-level system is proposed to produce high index of refraction with zero absorption in an Er^3+-doped yttrium aluminium garnet (YAG) crystal, which is achieved for a probe field between the excited state 4I13/2 and ground state 4I15/2 by adjusting a strong coherent driving field between the upper excited state 4I11/2 and 4I15/2. It is found that the changes of the frequency of the coherent driving field and the concentration of Er^3+ ions in the YAG crystal can maximize the index of refraction accompanied by vanishing absorption. This result could be useful for the dispersion compensation in fibre communication, laser particle acceleration, high precision magnetometry and so on.
基金the National Natural Science Foundation of China (No. 50674048)the Avigation Science Foundation of China (No. 2007ZF52062)
文摘Ce3+-doped Mn-Zn ferrite fibers were successfully prepared by the organic gel-thermal decomposition method from metal salts and citric acid. The composition,structure,and magnetic properties of these ferrite fibers were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),and vibrating sample magnetometer (VSM). The results show that Mn0.2Zn0.8Fe2-xCexO4 (x = 0-0.04) fibers are featured with an average grain size of 11.6-12.7 nm,with diameters ranging between 1.0 to 3.5 μm and a high ...
基金supported by the Key Research and Development Program of Hebei Province(No.21351501D)A Provincial and Ministerial Scientific Research Project(LJ20212C031165)Basic Frontier Science and Technology Innovation Project of Army Engineering University of PLA(KYSZJQZL2210)。
文摘Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target products were characterized by thermogravimetric analyzer,X-ray diffrotometer,fourier transform infrared spectrometer,scanning electron microscope,spectrophotometer and infrared emissivity tester,and the effects of Er^(3+)doping on its infrared and laser emissivity were studied.At the same time,the Sn_(1−x)Er_(x)O_(2)(x=0%,16%)doping models were constructed based on the first principles of density functional theory,and the related optoelectronic properties such as their energy band structure,density of states,reflectivity and dielectric constant were analyzed,and further explained the mechanism of Er^(3+)doping on SnO_(2)infrared emissivity and laser absorption from the point of electronic structure.The results showed that after calcination at 600℃,single rutile type SnO_(2)was formed,and the crystal structure was not changed by doping Er^(3+).The calcined products showed good fiber morphology,and the average fiber diameter was 402 nm.The infrared emissivity and resistivity of the samples both decreased first and then increased with the increase of Er^(3+)doping amount.When x=16%,the infrared emis-sivity of the sample was at least 0.71;and Er^(3+)doping can effectively reduce the reflectivity of SnO_(2)at 1.06μm and 1.55μm,when x=16%,its reflectivity at 1.06μm and 1.55μm are 50.5%and 40%,respectively,when x=24%,the reflectivity at 1.06μm and 1.55μm wavelengths are 47.3%and 42.1%,respectively.At the same time,the change of carrier concentration and electron transition before and after Er^(3+)doping were described by first-principle calculation,and the regulation mechanism of infrared emissivity and laser reflectivity was explained.This study provides a certain experimental and theoretical basis for the development of a single-type,light-weight and easily prepared infrared and laser compatible-stealth material.
文摘The .Er<sup>3+</sup>-Yb<sup>3+</sup>-doped fiber has a broadened absorption spectrum, which means the pumping sources can work efficiently from 810 to 1100nm. Among them 980nm is the maximum.absorption (10 dB/km) wavelength. By energy transferring and multiphoton process, the visible and ultraviolet radiation occurs when the Er<sup>3+</sup>-Yb<sup>3+</sup>-doped fiber is pumped by the laser at 980-nm band. Further researches on the mechanism of the fluorescence of Er<sup>3+</sup>-Yb<sup>3+</sup>-doped silica fiber pumped by Ti: A1<sub>2</sub>O<sub>3</sub> tunable laser at 980-nm band are helpful
基金the National Science Fund for Excellent Young Scholars(62022069)Shenzhen Science and Technology Projects(JCYJ20210324115813037)+2 种基金National Natural Science Foundation of China(62105272)Technology Development Program from Huawei Technologies Co.,Ltd.,Fundamental Research Funds for the Central Universities(20720200068)National Key Research and Development Program of China(2020YFC2200400).
文摘Green semiconductor lasers are still undeveloped,so high-power green lasers have heavily relied on nonlinear frequency conversion of near-infrared lasers,precluding compact and low-cost green laser systems.Here,we report the first Watt-level all-fiber CW Pr3t-doped laser operating directly in the green spectral region,addressing the aforementioned difficulties.The compact all-fiber laser consists of a double-clad Pr3t-doped fluoride fiber,two homemade fiber dichroic mirrors at visible wavelengths,and a 443-nm fiber-pigtailed pump source.Benefitting from>10 MW∕cm2 high damage intensity of our designed fiber dielectric mirror,the green laser can stably deliver 3.62-W of continuous-wave power at∼521 nm with a slope efficiency of 20.9%.To the best of our knowledge,this is the largest output power directly from green fiber lasers,which is one order higher than previously reported.Moreover,these green all-fiber laser designs are optimized by using experiments and numerical simulations.Numerical results are in excellent agreement with our experimental results and show that the optimal gain fiber length,output mirror reflectivity,and doping level should be considered to obtain higher power and efficiency.This work may pave a path toward compact high-power green all-fiber lasers for applications in biomedicine,laser display,underwater detection,and spectroscopy.
基金The authors are grateful to the Rising-star Project of Shanghai Municipal Science and Technology Commission(No.04QMX1448)the Project of Optical Science and Technology of Shanghai(No.022261046)the National Natural Science Foundation of China(No.60207006)for the support of this project.
文摘Based on the host of tellurite glasses, the glass formation, preform manufacture, and fiber fabrication are described. The characterization of amplified spontaneous emission (ASE) from this newly fabricated single-mode Er3+-doped tellurite fibers is also presented. When pumped at 980 nm, a very broad erbium ASE around 1.53 μm was observed. The variations of ASE with fiber length and pumping power are measured and discussed. The output of 2 mW from Er3+-doped tellurite fiber ASE source was obtained under the pump power of 660 mW.
基金supported by the National Natural Science Foundation of China(NSFC)(No.61805124)Natural Science Foundation of Ningbo City,China(No.2018A610023)+1 种基金3315 Innovation Team in Ningbo City,Zhejiang Province,ChinaK.C.Wong Magna Fund in Ningbo University,China。
文摘We report on the investigation of intermode beating mode-locked(IBML)pulse generation in a simple all-fiber Tm^3+-doped double clad fiber laser(TDFL).This IBML TDFL is implemented by matching longitudinal-mode frequency between 793 nm laser and TDFL without extra mode locker.The central wavelength of 1983 nm,the fundamental pulse frequency of 9.6 MHz and the signal-to-noise ratio(SNR)of>50 dB are achieved in this IBML TDFL.With laser cavity optimization,the IBML TDFL can finally generate an average output power of 1.03 W with corresponding pulse energy of 107 nJ.These results can provide an easily accessible way to develop compact large-energy,highpower TDFLs.