An LD directly-pumped solid-state laser is considered to be one of the most promising mid-infrared light sources because of its simple principle,small size,and compact structure for the generation of mid-infrared(MIR)...An LD directly-pumped solid-state laser is considered to be one of the most promising mid-infrared light sources because of its simple principle,small size,and compact structure for the generation of mid-infrared(MIR)lasers in the 3-5µm band.However,the quantum defect of LD directly-pumped MIR solid-state lasers will be much larger than that of ordinary near-infrared LD pumped solid-state lasers,which may lead to thermal damage and limit their development.In order to solve this problem,the methods of reducing the specific surface area of the crystal and improving the thermal energy released by the crystal structure are discussed,and the opti⁃mal length of the laser crystal is determined.The cooling structures of barium yttrium fluoride laser crystals(Ho^(3+):BY_(2)F_(8))of different lengths were studied by thermal simulation using COMSOL software.The experimen⁃tal results show that the output power can be increased and the thermal stress in the laser crystal can be alleviated by using the laser crystal whose length is slightly shorter than that of the cooler.The final experiment shows that when the pump repetition rate is 15 Hz and the pulse width is 90µs,the single pulse energy is 7.28 mJ at the out⁃put wavelength of 3.9µm,which is about 3 times as large as that of the crystal with the length of 10 mm(2.81 mJ).Such results should be another breakthrough of our team since the first directly-pumped solid-state MIR laser was realized more than a year ago.It might pave the way for the construction of a feasible MIR laser in the near future.展开更多
The 30 at.% Ho： BaY2F8 crystals were grown by the Czochralski method, and their spectroscopic properties are analyzed systematically by standard Judd–Ofelt theory. The Judd–Ofelt intensity parameters are estimated ...The 30 at.% Ho： BaY2F8 crystals were grown by the Czochralski method, and their spectroscopic properties are analyzed systematically by standard Judd–Ofelt theory. The Judd–Ofelt intensity parameters are estimated to be Ω2 =6.74 × 10^-20cm^2,Ω4 = 1.20 × 10^-20cm^2, and Ω6= 0.66 × 10^-20cm^2, and the fluorescence branching ratios and radiative lifetimes for a series of excited state manifolds are also determined. The emission cross sections with our measured infrared luminescence spectra, especially important for 4.1 μm, are calculated to be about 4.37 × 10^-21cm^2. The crystal quality is preliminarily tested through a mid-infrared laser emission experiment.展开更多
We present the recent research progress of our group on mid-infrared pulsed fiber lasers at 3μm by passive switching. Three different kinds of saturable absorbers including semiconductor saturable absorber （SESAM）,...We present the recent research progress of our group on mid-infrared pulsed fiber lasers at 3μm by passive switching. Three different kinds of saturable absorbers including semiconductor saturable absorber （SESAM）, Fe2＋：ZnSe crystal, topological insulator （TI） were used to perform the pulse generation, respectively. The temporal regimes of mode locking, Q-switching and Q-switching induced gain switching were gained. Some relative discussions and prospective efforts are proposed at the end of this paper.展开更多
As mid-infrared （MIR） lasers show numerous applications in the field of defense, medical, materials processing, and optical communications. Investigation on MIR Raman fiber lasers （RFL） increasingly becomes a hot ...As mid-infrared （MIR） lasers show numerous applications in the field of defense, medical, materials processing, and optical communications. Investigation on MIR Raman fiber lasers （RFL） increasingly becomes a hot topic. Compared with traditional silica fiber, fluoride and chalcogenide glass fibers possess higher nonlinear coefficients and excellent MIR transmittances. In this article, the latest development of the MIR RFL using fluoride and chalcogenide glass fibers as gain media are introduced, respectively. This review article mainly focuses on the development of MIR RFLs in aspects of output wavelength, output power and optical efficiency. The prospect of MIR RFLs is also discussed.展开更多
Preparation and optical characterisation of Erbium doped KY3F10 single crystals are reported. The crystals were grown using the Czochralski pulling technique. The single phase was controlled by X-ray diffraction analy...Preparation and optical characterisation of Erbium doped KY3F10 single crystals are reported. The crystals were grown using the Czochralski pulling technique. The single phase was controlled by X-ray diffraction analysis. Room temperature optical spectra were recorded between 200 and 1600 nm. They were used to fit the three phenomenological Judd-Ofelt (JO) parameters Ωt (t = 2, 4, 6). The emission transition probabilities, branching ratios and radiative lifetimes are then deduced. The possibility to use such material for laser emissions is discussed.展开更多
This was an outlook on the prediction of the infrared laser potentiality from concentration dependences of the 2F5/2 experimental decay time in Yb3＋-doped solid-state crystals mainly on cubic crystals with 99.99% pur...This was an outlook on the prediction of the infrared laser potentiality from concentration dependences of the 2F5/2 experimental decay time in Yb3＋-doped solid-state crystals mainly on cubic crystals with 99.99% purity which could be extended to laser ceramics of the same composition.展开更多
We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that t...We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that the thermal lens effect is gradually aggravated with the increase of working frequencies, and even working at 100 Hz, a single pulse energy of 234 m J can be achieved. A maximum average power of 41.5 W is achieved with a working frequency of 20 Hz and slope efficiency of 2.82%. This output power is much higher than other xenon lamp-pumped erbium laser devices.A Q-switched laser is demonstrated by using the TeO2crystal, the maximum output energies of 11.5 m J and 3.5 m J are obtained at 50 and 100 Hz, the corresponding peak powers are 93.4 k W and 17.2 kW, respectively.The laser wavelengths and beam quality factors are also characterized in the free-running and Q-switched modes. A higher pulse energy and peak power laser could be achieved further by improving the damage threshold of TeO2acousto-optical Q-switching. All the experimental results illustrate that the xenon lamp-pumped Er:YAP laser is a promising candidate for high-power and high-frequency mid-infrared laser devices.展开更多
Mid-infrared (MIR) laser sources operating in the 2.7–3μm spectral region have attracted extensive attention for many applications due to the unique features of locating at the atmospheric transparency window,corres...Mid-infrared (MIR) laser sources operating in the 2.7–3μm spectral region have attracted extensive attention for many applications due to the unique features of locating at the atmospheric transparency window,corresponding to the"characteristic fingerprint"spectra of several gas molecules,and strong absorption of water.Over the past two decades,significant developments have been achieved in 2.7–3μm MIR lasers benefiting from the sustainable innovations in laser technology and the great progress in material science.Here,we mainly summarize and review the recent progress of MIR bulk laser sources based on the rare-earth ions-doped crystals in the 2.7–3μm spectral region,including Er3+-,Ho3+-,and Dy3+-doped crystalline lasers.The outlooks and challenges for future development of rare-earth-doped MIR bulk lasers are also discussed.展开更多
High-power femtosecond mid-infrared(MIR)lasers are of vast importance to both fundamental research and applications.We report a high-power femtosecond master oscillator power amplifier laser system consisting of a sin...High-power femtosecond mid-infrared(MIR)lasers are of vast importance to both fundamental research and applications.We report a high-power femtosecond master oscillator power amplifier laser system consisting of a singlemode Er:ZBLAN fiber mode-locked oscillator and pre-amplifier followed by a large-mode-area Er:ZBLAN fiber main amplifier.The main amplifier is actively cooled and bidirectionally pumped at 976 nm,generating a slope efficiency of 26.9%.Pulses of 8.12 W,148 fs at 2.8μm with a repetition rate of 69.65 MHz are achieved.To the best of our knowledge,this is the highest average power ever achieved from a femtosecond MIR laser source.Such a compact ultrafast laser system is promising for a wide range of applications,such as medical surgery and material processing.展开更多
基金Supported by the National Key Research and Development Program of China(2021YFA0718803)。
文摘An LD directly-pumped solid-state laser is considered to be one of the most promising mid-infrared light sources because of its simple principle,small size,and compact structure for the generation of mid-infrared(MIR)lasers in the 3-5µm band.However,the quantum defect of LD directly-pumped MIR solid-state lasers will be much larger than that of ordinary near-infrared LD pumped solid-state lasers,which may lead to thermal damage and limit their development.In order to solve this problem,the methods of reducing the specific surface area of the crystal and improving the thermal energy released by the crystal structure are discussed,and the opti⁃mal length of the laser crystal is determined.The cooling structures of barium yttrium fluoride laser crystals(Ho^(3+):BY_(2)F_(8))of different lengths were studied by thermal simulation using COMSOL software.The experimen⁃tal results show that the output power can be increased and the thermal stress in the laser crystal can be alleviated by using the laser crystal whose length is slightly shorter than that of the cooler.The final experiment shows that when the pump repetition rate is 15 Hz and the pulse width is 90µs,the single pulse energy is 7.28 mJ at the out⁃put wavelength of 3.9µm,which is about 3 times as large as that of the crystal with the length of 10 mm(2.81 mJ).Such results should be another breakthrough of our team since the first directly-pumped solid-state MIR laser was realized more than a year ago.It might pave the way for the construction of a feasible MIR laser in the near future.
基金Project supported by the National Natural Science Foundation of China(Grant No.61275146)the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120002110066)the Special Program of the Co-construction with Beijing Municipal Government of China(Grant No.20121000302)
文摘The 30 at.% Ho： BaY2F8 crystals were grown by the Czochralski method, and their spectroscopic properties are analyzed systematically by standard Judd–Ofelt theory. The Judd–Ofelt intensity parameters are estimated to be Ω2 =6.74 × 10^-20cm^2,Ω4 = 1.20 × 10^-20cm^2, and Ω6= 0.66 × 10^-20cm^2, and the fluorescence branching ratios and radiative lifetimes for a series of excited state manifolds are also determined. The emission cross sections with our measured infrared luminescence spectra, especially important for 4.1 μm, are calculated to be about 4.37 × 10^-21cm^2. The crystal quality is preliminarily tested through a mid-infrared laser emission experiment.
基金supported by the National Natural Science Foundation of China under Grant No.61377042the Fundamental Research Funds for the Central Universities under Grant No.ZYGX2013J058the Program for New Century Excellent Talents in University of Ministry of Education of China under Grant No.NCET-13-0094
文摘We present the recent research progress of our group on mid-infrared pulsed fiber lasers at 3μm by passive switching. Three different kinds of saturable absorbers including semiconductor saturable absorber （SESAM）, Fe2＋：ZnSe crystal, topological insulator （TI） were used to perform the pulse generation, respectively. The temporal regimes of mode locking, Q-switching and Q-switching induced gain switching were gained. Some relative discussions and prospective efforts are proposed at the end of this paper.
基金supported by the Fundamental Research Funds for the Central Universities under Grant No.ZYGX2015KYQD015
文摘As mid-infrared （MIR） lasers show numerous applications in the field of defense, medical, materials processing, and optical communications. Investigation on MIR Raman fiber lasers （RFL） increasingly becomes a hot topic. Compared with traditional silica fiber, fluoride and chalcogenide glass fibers possess higher nonlinear coefficients and excellent MIR transmittances. In this article, the latest development of the MIR RFL using fluoride and chalcogenide glass fibers as gain media are introduced, respectively. This review article mainly focuses on the development of MIR RFLs in aspects of output wavelength, output power and optical efficiency. The prospect of MIR RFLs is also discussed.
文摘Preparation and optical characterisation of Erbium doped KY3F10 single crystals are reported. The crystals were grown using the Czochralski pulling technique. The single phase was controlled by X-ray diffraction analysis. Room temperature optical spectra were recorded between 200 and 1600 nm. They were used to fit the three phenomenological Judd-Ofelt (JO) parameters Ωt (t = 2, 4, 6). The emission transition probabilities, branching ratios and radiative lifetimes are then deduced. The possibility to use such material for laser emissions is discussed.
文摘This was an outlook on the prediction of the infrared laser potentiality from concentration dependences of the 2F5/2 experimental decay time in Yb3＋-doped solid-state crystals mainly on cubic crystals with 99.99% purity which could be extended to laser ceramics of the same composition.
基金supported by the Natural Science Foundation of Anhui Province (Grant No. 2208085QF217)the National Natural Science Foundation of China (Grant No. 52102012)the Hefei Institutes of Physical Science (HFIPS) Director’s Fund (Grant No. YZJJ2022QN08)。
文摘We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that the thermal lens effect is gradually aggravated with the increase of working frequencies, and even working at 100 Hz, a single pulse energy of 234 m J can be achieved. A maximum average power of 41.5 W is achieved with a working frequency of 20 Hz and slope efficiency of 2.82%. This output power is much higher than other xenon lamp-pumped erbium laser devices.A Q-switched laser is demonstrated by using the TeO2crystal, the maximum output energies of 11.5 m J and 3.5 m J are obtained at 50 and 100 Hz, the corresponding peak powers are 93.4 k W and 17.2 kW, respectively.The laser wavelengths and beam quality factors are also characterized in the free-running and Q-switched modes. A higher pulse energy and peak power laser could be achieved further by improving the damage threshold of TeO2acousto-optical Q-switching. All the experimental results illustrate that the xenon lamp-pumped Er:YAP laser is a promising candidate for high-power and high-frequency mid-infrared laser devices.
基金supported by the National Natural Science Foundation of China (Nos. 61975095, 61975097, and 61308042)the Young Scholars Program of Shandong University (No. 2017WLJH48)+1 种基金the Youth Cross Innovation Group of Shandong University (No. 2020QNQT)the Financial Support from Qilu Young Scholar of Shandong University
文摘Mid-infrared (MIR) laser sources operating in the 2.7–3μm spectral region have attracted extensive attention for many applications due to the unique features of locating at the atmospheric transparency window,corresponding to the"characteristic fingerprint"spectra of several gas molecules,and strong absorption of water.Over the past two decades,significant developments have been achieved in 2.7–3μm MIR lasers benefiting from the sustainable innovations in laser technology and the great progress in material science.Here,we mainly summarize and review the recent progress of MIR bulk laser sources based on the rare-earth ions-doped crystals in the 2.7–3μm spectral region,including Er3+-,Ho3+-,and Dy3+-doped crystalline lasers.The outlooks and challenges for future development of rare-earth-doped MIR bulk lasers are also discussed.
基金the National Natural Science Foundation of China(61975136,61935014,62105222,61775146,61905151)the Basic and Applied Basic Research Foundation of Guangdong Province(2019A1515010699)+1 种基金the Shenzhen Science and Technology Innovation Program(CJGJZD20200617103003009,JCYJ20210324094400001,GJHZ20210705141801006)the Beijing Natural Science Foundation(JQ21019).
文摘High-power femtosecond mid-infrared(MIR)lasers are of vast importance to both fundamental research and applications.We report a high-power femtosecond master oscillator power amplifier laser system consisting of a singlemode Er:ZBLAN fiber mode-locked oscillator and pre-amplifier followed by a large-mode-area Er:ZBLAN fiber main amplifier.The main amplifier is actively cooled and bidirectionally pumped at 976 nm,generating a slope efficiency of 26.9%.Pulses of 8.12 W,148 fs at 2.8μm with a repetition rate of 69.65 MHz are achieved.To the best of our knowledge,this is the highest average power ever achieved from a femtosecond MIR laser source.Such a compact ultrafast laser system is promising for a wide range of applications,such as medical surgery and material processing.
