In this paper, the theoretical rate equation model of an in-band pumped gain-switched thulium-doped fiber (TDF) laser is investigated. The analytical formulations of pump energy threshold, peak power extraction effi...In this paper, the theoretical rate equation model of an in-band pumped gain-switched thulium-doped fiber (TDF) laser is investigated. The analytical formulations of pump energy threshold, peak power extraction efficiency, and pulse extraction efficiency are derived through analyzing the interaction process between the pump pulse and the laser pulse. They are useful for understanding, designing, and optimizing the in-band pumped TDF lasers in a 1.9 μm-2.1 μm wavelength region. The experiment with an all-fiber gain-switched TDF laser pumped by a 1.558-μm pulse amplifier is conducted, and our experimental results show good agreement with theoretical analysis.展开更多
We have made a gain-switched all-solid-state quasi-continuous-wave (QCW) tunable Ti:sapphire laser system, which is pumped by a 532 nm intracavity frequency-doubled Nd:YAG laser. Based on the theory of gain-switch...We have made a gain-switched all-solid-state quasi-continuous-wave (QCW) tunable Ti:sapphire laser system, which is pumped by a 532 nm intracavity frequency-doubled Nd:YAG laser. Based on the theory of gain-switching and the study on the influencing factors of the output pulse width, an effective method for obtaining high power and narrow pulse width output is proposed. Through deliberately designing the pump source and the resonator of the Ti:sapphire laser, when the repetition rate is 6 kHz and the length of the cavity is 220 mm, at an incident pump power of 22 W, the tunable Ti:sapphire laser from 700 to 950nm can be achieved. It has a maximum average output power of 5.6W at 800nm and the pulse width of 13.2 ns, giving an optical conversion efficiency of 25.5% from the 532 mn pump laser to the Ti:sapphire laser.展开更多
Random lasers are a type of lasers that lack typical resonator structures,offering benefits such as easy integration,low cost,and low spatial coherence.These features make them popular for speckle-free imaging and ran...Random lasers are a type of lasers that lack typical resonator structures,offering benefits such as easy integration,low cost,and low spatial coherence.These features make them popular for speckle-free imaging and random number generation.However,due to their high threshold and phase instability,the production of picosecond random lasers has still been a challenge.In this work,we have developed three dyes incorporating polymer optical fibers doped with various scattering nanoparticles to produce short-pulsed random fiber lasers.Notably,stable picosecond random laser emission lasting600 ps is observed at a low pump energy of 50μJ,indicating the gain-switching mechanism.Population inversion and gain undergo an abrupt surge as the intensity of the continuously pumped light nears the threshold level.When the intensity of the continuously pumped light reaches a specific value,the number of inversion populations in the“scattering cavity”surpasses the threshold rapidly.Simulation results based on a model that considers power-dependent gain saturation confirmed the above phenomenon.This research helps expand the understanding of the dynamics behind random medium-stimulated emission in random lasers and opens up possibilities for mode locking in these systems.展开更多
Mid-infrared(MIR)fiber pulsed lasers are of tremendous application interest in eye-safe LIDAR,spectroscopy,chemical detection and medicine.So far,these MIR lasers largely required bulk optical elements,complex free-sp...Mid-infrared(MIR)fiber pulsed lasers are of tremendous application interest in eye-safe LIDAR,spectroscopy,chemical detection and medicine.So far,these MIR lasers largely required bulk optical elements,complex free-space light alignment and large footprint,precluding compact all-fiber structure.Here,we proposed and demonstrated an all-fiberized structured gain-switched Ho3+-doped ZBLAN fiber laser operating around 2.9μm.A home-made 1146 nm Raman fiber pulsed laser was utilized to pump highly concentrated single-cladding Ho3+-doped ZBLAN fiber with different lengths of 2 m or 0.25 m.A home-made MIR fiber mirror and a perpendicular-polished ZBLAN fiber end construct the all-fiberized MIR cavity.Stable gain-switched multiple states with a sub-pulse number tuned from 1 to 8 were observed.The effects of gain fiber length,pump power,pump repetition rate and output coupling ratio on performance of gain-switched pulses were further investigated in detail.The shortest pulse duration of 283 ns was attained with 10 kHz repetition rate.The pulsed laser,centered at 2.92μm,had a maximum average output power of 54.2 mW and a slope efficiency of 10.12%.It is,to the best of our knowledge,the first time to demonstrate a mid-infrared gain-switched Ho3+:ZBLAN fiber laser with compact all-fiber structure.展开更多
The generation of mid-infrared pulsed lasers was achieved in a Ho3+:YAG laser pumped gain-switched Cr^2+:Cd Se laser system with the shortest pulse duration of 4.15 ns.With a pump pulse duration of 50 ns and pump powe...The generation of mid-infrared pulsed lasers was achieved in a Ho3+:YAG laser pumped gain-switched Cr^2+:Cd Se laser system with the shortest pulse duration of 4.15 ns.With a pump pulse duration of 50 ns and pump power of 2.7 W,the gain-switched Cr^2+:Cd Se laser achieved over 10 times pulse narrowing,obtaining the maximum peak power of 5.7 k W.The optical-to-optical conversion efficiency was 3.7%,which could be further improved with better crystal surface polishing quality.The laser central wavelength was measured to be 2.65μm with a bandwidth(FWHM)of 50 nm.In addition,the parameter optimization for suppressing the pulse tail was discussed,while the long cavity and high output transmissivity contributed to obtaining the single-peak pulses.展开更多
A 1.7μm gain-switched thulium-doped all-fiber laser with a master oscillator power amplifier(MOPA)configuration,utilizing a bandpass fiber filter and a 1550 nm erbium/ytterbium-codoped fiber MOPA,is demonstrated.The ...A 1.7μm gain-switched thulium-doped all-fiber laser with a master oscillator power amplifier(MOPA)configuration,utilizing a bandpass fiber filter and a 1550 nm erbium/ytterbium-codoped fiber MOPA,is demonstrated.The influences of pump pulse parameters(repetition rate and pulse duration)and laser cavity structures(ring and linear)on the laser performances were experimentally investigated.To the best of our knowledge,the power quenching and drop were observed in the 1.7μm gain-switched thulium-doped fiber lasers for the first time,resulting from the mode-locked-resembling operation and nonlinear effects.Moreover,the fiber ring-cavity laser was more stable than the linear-cavity laser in the time domain and power.Finally,a laser with a maximum average power of 1.687 W,a slope efficiency of 19.7%,a single-pulse energy of 16.87μJ,a pulse width of 425 ns,a repetition rate of 100 kHz and a peak power of 39.69 W was obtained.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 60878011 and 61078008)the Program for New Century ExcellentTalents in University,China (Grant No. NCET-10-0067)
文摘In this paper, the theoretical rate equation model of an in-band pumped gain-switched thulium-doped fiber (TDF) laser is investigated. The analytical formulations of pump energy threshold, peak power extraction efficiency, and pulse extraction efficiency are derived through analyzing the interaction process between the pump pulse and the laser pulse. They are useful for understanding, designing, and optimizing the in-band pumped TDF lasers in a 1.9 μm-2.1 μm wavelength region. The experiment with an all-fiber gain-switched TDF laser pumped by a 1.558-μm pulse amplifier is conducted, and our experimental results show good agreement with theoretical analysis.
基金Project supported in part by the National Natural Science Foundation of China (Grant Nos 60637010 and 60671036)the National Basic Research Program of China (Grant No 2007CB310403)Tianjin Applied Fundamental Research Project (Grant No07JCZDJC05900)
文摘We have made a gain-switched all-solid-state quasi-continuous-wave (QCW) tunable Ti:sapphire laser system, which is pumped by a 532 nm intracavity frequency-doubled Nd:YAG laser. Based on the theory of gain-switching and the study on the influencing factors of the output pulse width, an effective method for obtaining high power and narrow pulse width output is proposed. Through deliberately designing the pump source and the resonator of the Ti:sapphire laser, when the repetition rate is 6 kHz and the length of the cavity is 220 mm, at an incident pump power of 22 W, the tunable Ti:sapphire laser from 700 to 950nm can be achieved. It has a maximum average output power of 5.6W at 800nm and the pulse width of 13.2 ns, giving an optical conversion efficiency of 25.5% from the 532 mn pump laser to the Ti:sapphire laser.
基金supported by the National Natural Science Foundation of China(Nos.12174002,11874012,11874126,and 51771186)the Excellent Scientific Research and Innovation Team of Anhui Province(No.2022AH010003)+3 种基金the Key Research and Development Plan of Anhui Province(No.202104a05020059)the Innovation Project for the ReturnedOverseasScholarsofAnhuiProvince(No.2021LCX011)the University Synergy Innovation Program of Anhui Province(No.GXXT-2020-052)the Anhui Young Wanjiang Scholars Talent Project(No.Z010118167)。
文摘Random lasers are a type of lasers that lack typical resonator structures,offering benefits such as easy integration,low cost,and low spatial coherence.These features make them popular for speckle-free imaging and random number generation.However,due to their high threshold and phase instability,the production of picosecond random lasers has still been a challenge.In this work,we have developed three dyes incorporating polymer optical fibers doped with various scattering nanoparticles to produce short-pulsed random fiber lasers.Notably,stable picosecond random laser emission lasting600 ps is observed at a low pump energy of 50μJ,indicating the gain-switching mechanism.Population inversion and gain undergo an abrupt surge as the intensity of the continuously pumped light nears the threshold level.When the intensity of the continuously pumped light reaches a specific value,the number of inversion populations in the“scattering cavity”surpasses the threshold rapidly.Simulation results based on a model that considers power-dependent gain saturation confirmed the above phenomenon.This research helps expand the understanding of the dynamics behind random medium-stimulated emission in random lasers and opens up possibilities for mode locking in these systems.
基金National Natural Science Foundation of China(Nos.61475129,11674269)Fundamental Research Funds for the Central Universities(No.20720180057)Natural Science Foundation of Fujian Province for Distinguished Young Scientists(No.2017J06016)。
文摘Mid-infrared(MIR)fiber pulsed lasers are of tremendous application interest in eye-safe LIDAR,spectroscopy,chemical detection and medicine.So far,these MIR lasers largely required bulk optical elements,complex free-space light alignment and large footprint,precluding compact all-fiber structure.Here,we proposed and demonstrated an all-fiberized structured gain-switched Ho3+-doped ZBLAN fiber laser operating around 2.9μm.A home-made 1146 nm Raman fiber pulsed laser was utilized to pump highly concentrated single-cladding Ho3+-doped ZBLAN fiber with different lengths of 2 m or 0.25 m.A home-made MIR fiber mirror and a perpendicular-polished ZBLAN fiber end construct the all-fiberized MIR cavity.Stable gain-switched multiple states with a sub-pulse number tuned from 1 to 8 were observed.The effects of gain fiber length,pump power,pump repetition rate and output coupling ratio on performance of gain-switched pulses were further investigated in detail.The shortest pulse duration of 283 ns was attained with 10 kHz repetition rate.The pulsed laser,centered at 2.92μm,had a maximum average output power of 54.2 mW and a slope efficiency of 10.12%.It is,to the best of our knowledge,the first time to demonstrate a mid-infrared gain-switched Ho3+:ZBLAN fiber laser with compact all-fiber structure.
基金supported by the National Key Research and Development Program of China(No.2017YFB1104500)the China Postdoctoral Science Foundation(No.2018M630355)the National Natural Science Foundation of China(Nos.61905128 and61905150)。
文摘The generation of mid-infrared pulsed lasers was achieved in a Ho3+:YAG laser pumped gain-switched Cr^2+:Cd Se laser system with the shortest pulse duration of 4.15 ns.With a pump pulse duration of 50 ns and pump power of 2.7 W,the gain-switched Cr^2+:Cd Se laser achieved over 10 times pulse narrowing,obtaining the maximum peak power of 5.7 k W.The optical-to-optical conversion efficiency was 3.7%,which could be further improved with better crystal surface polishing quality.The laser central wavelength was measured to be 2.65μm with a bandwidth(FWHM)of 50 nm.In addition,the parameter optimization for suppressing the pulse tail was discussed,while the long cavity and high output transmissivity contributed to obtaining the single-peak pulses.
基金financially supported by the National Natural Science Foundation of China(62005312,62090065,and 61935006)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(2022409)the Key Research and Development Projects of Shaanxi Province(2022GY-423)。
文摘A 1.7μm gain-switched thulium-doped all-fiber laser with a master oscillator power amplifier(MOPA)configuration,utilizing a bandpass fiber filter and a 1550 nm erbium/ytterbium-codoped fiber MOPA,is demonstrated.The influences of pump pulse parameters(repetition rate and pulse duration)and laser cavity structures(ring and linear)on the laser performances were experimentally investigated.To the best of our knowledge,the power quenching and drop were observed in the 1.7μm gain-switched thulium-doped fiber lasers for the first time,resulting from the mode-locked-resembling operation and nonlinear effects.Moreover,the fiber ring-cavity laser was more stable than the linear-cavity laser in the time domain and power.Finally,a laser with a maximum average power of 1.687 W,a slope efficiency of 19.7%,a single-pulse energy of 16.87μJ,a pulse width of 425 ns,a repetition rate of 100 kHz and a peak power of 39.69 W was obtained.