Owing to the dynamic tunability and strong confinement,graphene plasmons(GPs)have emerged as an excellent candidate for the manipulation of light-matter interaction.Surface plasmons(SPs)have been admitted as another e...Owing to the dynamic tunability and strong confinement,graphene plasmons(GPs)have emerged as an excellent candidate for the manipulation of light-matter interaction.Surface plasmons(SPs)have been admitted as another effective way allowing strong confinement of light at the nanoscale.The combination of GPs and SPs like localized surface plasmons(LSPs)and propagating surface plasmon polaritons(SPPs)will lead to a synergistic effect that could remarkably improve light-matter interactions,showing great potential for many applications for the improvement of solar cell efficiency,biosensor sensitivity,and the performance of photonic devices.In this study,the GPs were activated by placing graphene film onto a two-dimensional(2D)phase-changing crystalline Ge_(2)Sb_(1.5)Bi_(0.5)Te_(5)(cGSBT)nanograting structure,which also acts as an original source generating LSPs.The SPPs originated by laying the above structure onto an Au mirror.The combined effects of GPs,LSPs,and SPPs are epitomized in such a simple Gr/2D cGSBT gratings/Au heterostructure,which allows easy realization of an ultrafast mode-locked laser quite stable working at 1550 nm range due to the strong nonlinear optical absorption capability.This approach overcomes the heat and energy loss in metallic gratings or a Gr-based heterostructure,exhibiting great potential for applications in the design and fabrication of photonic devices.展开更多
Ultrashort pulses were generated in passively mode-locked Nd：YAC and Nd：CdVO4 lasers pumped by a pulsed laser diode with 10-Hz repetition rate. Stable mode-locked pulse trains were produced with the pulse width of 1...Ultrashort pulses were generated in passively mode-locked Nd：YAC and Nd：CdVO4 lasers pumped by a pulsed laser diode with 10-Hz repetition rate. Stable mode-locked pulse trains were produced with the pulse width of 10 ps. The evolution of the mode-locked pulse was observed in the experiment and was discussed in detail. Comparing the pulse evolutions of Nd：YAG and Nd：GdVO4 lasers, we found that the buildup time of the steady-state mode-locking with semiconductor saturable absorber mirrors （SESAMs） was relevant to the upper-state lifetime and the emission cross-section of the gain medium.展开更多
We report on the generation of Q-switched and Q-switched mode-locked （QML） pulses in an erbium-doped fiber ring laser by using a polyvinyl alcohol （PVA） -based gold nanorod （GNR） saturable absorber （SA）. The P...We report on the generation of Q-switched and Q-switched mode-locked （QML） pulses in an erbium-doped fiber ring laser by using a polyvinyl alcohol （PVA） -based gold nanorod （GNR） saturable absorber （SA）. The PVA- based GNR SA has a modulation depth of -4.8% and a non-saturable loss of -26.9% at 1.5 μm. A Q-switched pulse train with a repetition rate varying from 18.70 to 39.85 kHz and a QML pulse train with an envelope repetition rate tuning from 20.31 to 31.50 kHz are obtained. Moreover, the lasing wavelengths of the Q-switched pulses can be flexibly tuned by introducing a narrow bandwidth, tunable filter into the laser cavity. The results demonstrate that the GNRs exhibit good optical performance and can find a wide range of applications in the field of laser technology.展开更多
A new technique for seed-injection locking of single-axial-mode （SAM） Q-switched Nd：YAG laser is reported. The technique called energy reduction （ER） is utilized when SAM operation is locked to design its feedbac...A new technique for seed-injection locking of single-axial-mode （SAM） Q-switched Nd：YAG laser is reported. The technique called energy reduction （ER） is utilized when SAM operation is locked to design its feedback scheme. This method ensures long-term 100% seed-injection locking performance and the pulsed SAM output energy can reach as high as 200 mJ. Both temporal and spatial interferometric experiments have been executed to confirm the SAM oscillation.展开更多
We experimentally demonstrate a femtosecond optical parametric oscillator （OPO） synchronously pmnped by a home-made solid-state mode-locking Yb：YCOB laser, which is capable of laser pulse as short as 102 fs and ave...We experimentally demonstrate a femtosecond optical parametric oscillator （OPO） synchronously pmnped by a home-made solid-state mode-locking Yb：YCOB laser, which is capable of laser pulse as short as 102 fs and average power of 620 mW at the central wavelength of 1052 nm. By using a periodically poled lithium niobate with tuning of the grating periods from 28.5 to 31.5μm as the nonlinear gain crystal, tunable femtosecond pulses from 1444 to 1683 nm are realized by conveniently adjusting the OPO cavity length with 76.8 MHz repetition rate. The maximum average output power is 152 mW at 1568 nm, corresponding to an idler power of 75 mW at 3197 nm as well as 36.6% total extraction efficiency.展开更多
Mode-locked fiber lasers are excellent platforms for soliton generation.Solitons exhibit distinct distribution and evolution characteristics depending on the net dispersion of the laser cavity.Here we propose an exper...Mode-locked fiber lasers are excellent platforms for soliton generation.Solitons exhibit distinct distribution and evolution characteristics depending on the net dispersion of the laser cavity.Here we propose an experimental scheme to reconstruct the intracavity dynamics of solitons within a mode-locked fiber laser.The proposed scheme is facilitated by disposing multiple output ports at different positions throughout the cavity,thereby enabling indepth observation and manipulation of soliton evolution along the dispersion map.The experimental results verify corresponding simulations and explain some phenomena from the perspective of soliton evolution.Our results offer a pathway for comprehensive analyses of intracavity pulse dynamics,fostering advancements in nonlinear and ultrafast optics.展开更多
Polygonal optical vortices—a new subset of optical vortices—uniquely enable numerous applications due to the new degrees of freedom offered and their customizable light intensity structure.So far,their generation ha...Polygonal optical vortices—a new subset of optical vortices—uniquely enable numerous applications due to the new degrees of freedom offered and their customizable light intensity structure.So far,their generation has only been reported for continuous wave.Here,we demonstrate the first femtosecond polygonal optical vortex pulses,which is also the first pulsed demonstration of such vortices in general.From a mode-locked Yb:KGW laser oscillator,femtosecond Hermit-Gaussian pulses at the quasi-frequency-degenerate state were generated and subsequently converted by astigmatic mode conversion to femtosecond polygonal optical vortices.They have light intensity distributions of square,pentagonal,and hexagonal shapes and carry orbital angular momentums.In all these variations,the average power and pulse duration are greater than one watt and less than 500 fs.These results open the way to new applications in the fields of femtosecond optical tweezer and three-dimensional microstructure fabrication.展开更多
Harmonic mode-locking,realized actively or passively,is an effective technique for increasing the repetition rate of ultrafast lasers.It is critically important to understand how a harmonically mode-locked pulse train...Harmonic mode-locking,realized actively or passively,is an effective technique for increasing the repetition rate of ultrafast lasers.It is critically important to understand how a harmonically mode-locked pulse train responds to external perturbations and noise,so as to make sure that it is stable and resistant to noise.Here,in a series of carefully designed experiments,we elucidate the retiming dynamics of laser pulses generated in a soliton fiber laser harmonically modelocked at GHz frequencies to the acoustic resonance in a photonic crystal fiber(PCF)core.We characterize the selfdriven optomechanical lattice,which is distributed along the PCF and provides the structure that supports harmonic mode-locking,using a homodyne setup.We reveal that,after an abrupt perturbation,each soliton in the lattice undergoes damped oscillatory retiming within its trapping potential,while the retiming is strongly coupled to soliton dissipation.In addition,we show,through statistical analysis of the intra-cavity pulse spacing,how the trapping potentials are effective for suppressing timing jtter.The measurements and the theory developed in this work lay the groundwork for studies of the general stability and noise performance of harmonically mode-locked lasers as well as providing valuable insight into generic multi-pulse phenomena in mode-locked lasers.展开更多
The complexity of multi-dimensional optical wave dynamics arises from the introduction of multiple degrees of freedom and their intricate interactions.In comparison to multimode spatiotemporal mode-locked solitons,exp...The complexity of multi-dimensional optical wave dynamics arises from the introduction of multiple degrees of freedom and their intricate interactions.In comparison to multimode spatiotemporal mode-locked solitons,expanding the wavelength dimension is also crucial for studying the dynamics of multi-dimensional solitons,with simpler characterization techniques。展开更多
We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of -230 MHz was achieved and th...We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of -230 MHz was achieved and the pulse train was modulated by the Q-switched envelope with the repetition rate of -150 kHz. The maximum output of 4 W was obtained under the pump power of 13.5 W. The optical-to-optical efficiency was 30%. We also discussed the transition of each process having emerged.展开更多
We report a diode end-pumped continuous wave (CW) passively mode-locked Nd:YVO4 laser with a homemade semiconductor saturable absorber mirror (SESAM). The maximum average output power is 5.3 W at the incident pump pow...We report a diode end-pumped continuous wave (CW) passively mode-locked Nd:YVO4 laser with a homemade semiconductor saturable absorber mirror (SESAM). The maximum average output power is 5.3 W at the incident pump power of 17 W, which corresponds to an optical-optical conversion efficiency of 31.2% and slope efficiency of 34.7%. The corresponding optical spectrum has a 0.2-nm full width at half maximum (FWHM). and the pulse repetition rate is 83 MHz.展开更多
A 10-GHz soliton source with pulse duration between 4-8 ps and wavelength continuously tunable from 1530 nm to 1563 nm is presented. Using regeneratively mode-locking technology, the harmonically mode-locked fiber rin...A 10-GHz soliton source with pulse duration between 4-8 ps and wavelength continuously tunable from 1530 nm to 1563 nm is presented. Using regeneratively mode-locking technology, the harmonically mode-locked fiber ring laser could work without pulse dropout at room temperature when no cavity length or polarization maintaining mechanism is available. Applying only one 980-nm laser diode pump, the average output power reaches more than 4 mW.展开更多
The nonlinear optical loop mirror (NOLM) is used as a saturable absorbed to reshape pulses. Experimentally, an actively mode-locked erbium-doped fiber ring laser with figure-eight structure is set up. 2 - 4 order harm...The nonlinear optical loop mirror (NOLM) is used as a saturable absorbed to reshape pulses. Experimentally, an actively mode-locked erbium-doped fiber ring laser with figure-eight structure is set up. 2 - 4 order harmonic pulse train with stable amplitude has been obtained when the RF modulation frequency is about 2.5 GHz.展开更多
A diode-pumped Yb3+:YAl3(BO3)3 (Yb:YAB) laser system was demonstrated with continuous wave (CW) and pulsed output. The polarized CW outputs and femtosecond mode-locked lasers with semiconductor saturable-absorber mirr...A diode-pumped Yb3+:YAl3(BO3)3 (Yb:YAB) laser system was demonstrated with continuous wave (CW) and pulsed output. The polarized CW outputs and femtosecond mode-locked lasers with semiconductor saturable-absorber mirrors (SESAM) at the fundamental wavelength were measured. For the CW output, polarization ratios were 88.1% (for e-ray) and 87.2% (for o-ray). For the mode-locked system, polarization ratio reached 38.5%, and the repetition frequency was 117.6 MHz.展开更多
A wavelength tunable, high repetition rate mode-locked fiber ring laser was demonstrated. In the experiment, photonic crystal fiber （PCF） is used as an intracavity compression medium. The high nonlinearity and anoma...A wavelength tunable, high repetition rate mode-locked fiber ring laser was demonstrated. In the experiment, photonic crystal fiber （PCF） is used as an intracavity compression medium. The high nonlinearity and anomalous dispersion of PCF can cause intracavity compression and result in significant reduction in the pulse width. The pulses duration at the repetition rate of 9.99 GHz was less than 10 ps over the range of 1532-1565 nm.展开更多
Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the puls...Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.展开更多
A diode-pumped passively Q-switched Nd：YLF laser was demonstrated by using saturable absorber of Cr^4＋：YAG. At the incident power of 7.74 W, pure passively Q-switched laser with per pulse energy of 210 μJ and puls...A diode-pumped passively Q-switched Nd：YLF laser was demonstrated by using saturable absorber of Cr^4＋：YAG. At the incident power of 7.74 W, pure passively Q-switched laser with per pulse energy of 210 μJ and pulse width of 19.6 ns at repetition rate of 1.78 kHz was obtained by using Cr^4＋：YAG with initial transmission of 80%. At the incident power of 8.70 W, a Q-switched mode-locking with average output power of 650 mW was achieved, the overall slop efficiency was 16%, corresponding to the initial transmission of 85% of Cr^4＋ ：YAG.展开更多
We propose a low-threshold soliton fiber laser passively mode locked with two different types of film-like saturable absorbers, one of which is fabricated by mixing Bi2Te3 with de-ionized water, as well as polyvinyl a...We propose a low-threshold soliton fiber laser passively mode locked with two different types of film-like saturable absorbers, one of which is fabricated by mixing Bi2Te3 with de-ionized water, as well as polyvinyl alcohol（PVA）, and then evaporating them in a Petri dish, and the other of which is prepared by directly dropping Bi2Te3 solution on the PVA film. Both Bi2Te3–PVA films exhibit outstanding features of low loss, high flexibility, and easy synthesis. By incorporating Bi2Te3–PVA films into fiber lasers, stable single-soliton emissions are obtained at a low pump power of 13 mW. Our results suggest that the Bi2Te3 can work as a promising mode locker for ultrafast lasers,while PVA is an excellent host for fabricating high-performance film-based saturable absorbers.展开更多
A frequency-stabilized laser system at 1572 nm for space-borne carbon dioxide （CO2） detection LIDAR to realize the precise measurement of the global atmospheric CO2 concentration is presented in this Letter. A distr...A frequency-stabilized laser system at 1572 nm for space-borne carbon dioxide （CO2） detection LIDAR to realize the precise measurement of the global atmospheric CO2 concentration is presented in this Letter. A distributed- feedback laser diode serves as the master laser （ML） and is wavelength locked to the CO2 line center at 1572.0179 nm using the external frequency modulation technique. The root mean square frequency drift is sup- pressed to about 50 kHz at an average time of 0.1 s over 8 h. Based on optical phase-locked loops, an online seeder and an offiine seeder are offset locked to the reference laser at 1572.024 and 1572.081 nm, respectively, retaining virtually the same frequency stability as the ML.展开更多
An optimized dual fiber Bragg grating （FBG） is proposed for 980-nm semiconductor lasers without thermoelectric coolers to restrict temperature-induced wavelength shift.The mathematical model of the temperature-induc...An optimized dual fiber Bragg grating （FBG） is proposed for 980-nm semiconductor lasers without thermoelectric coolers to restrict temperature-induced wavelength shift.The mathematical model of the temperature-induced wavelength shift of the laser with the dual FBG is built using the external cavity feedback rate equations.The external cavity parameters are optimized for achieving the stability mode-locking laser output.The spectral characteristics of the dual FBG stabilized laser are measured to range from 0 to 70 °C.The side mode suppression ratio （SMSR） is more than 45 dB,while the full-width at half-maximum （FWHM） is less than 1 nm.The peak wavelength shift is less than 0.1 nm.The dual FBG wavelength shift proportional coefficient is between 0.1086 and 0.4342.展开更多
基金National Natural Science Foundation of China(62404116)Natural Science Foundation of Shandong Province(ZR2023QE216)Youth Innovation Team Project of Shandong Province(2023KJ235)。
文摘Owing to the dynamic tunability and strong confinement,graphene plasmons(GPs)have emerged as an excellent candidate for the manipulation of light-matter interaction.Surface plasmons(SPs)have been admitted as another effective way allowing strong confinement of light at the nanoscale.The combination of GPs and SPs like localized surface plasmons(LSPs)and propagating surface plasmon polaritons(SPPs)will lead to a synergistic effect that could remarkably improve light-matter interactions,showing great potential for many applications for the improvement of solar cell efficiency,biosensor sensitivity,and the performance of photonic devices.In this study,the GPs were activated by placing graphene film onto a two-dimensional(2D)phase-changing crystalline Ge_(2)Sb_(1.5)Bi_(0.5)Te_(5)(cGSBT)nanograting structure,which also acts as an original source generating LSPs.The SPPs originated by laying the above structure onto an Au mirror.The combined effects of GPs,LSPs,and SPPs are epitomized in such a simple Gr/2D cGSBT gratings/Au heterostructure,which allows easy realization of an ultrafast mode-locked laser quite stable working at 1550 nm range due to the strong nonlinear optical absorption capability.This approach overcomes the heat and energy loss in metallic gratings or a Gr-based heterostructure,exhibiting great potential for applications in the design and fabrication of photonic devices.
基金This work was supported by the National Nature Science Foundation of Beijing under Grant No. 3021001 and the foundation of Liaocheng University.
文摘Ultrashort pulses were generated in passively mode-locked Nd：YAC and Nd：CdVO4 lasers pumped by a pulsed laser diode with 10-Hz repetition rate. Stable mode-locked pulse trains were produced with the pulse width of 10 ps. The evolution of the mode-locked pulse was observed in the experiment and was discussed in detail. Comparing the pulse evolutions of Nd：YAG and Nd：GdVO4 lasers, we found that the buildup time of the steady-state mode-locking with semiconductor saturable absorber mirrors （SESAMs） was relevant to the upper-state lifetime and the emission cross-section of the gain medium.
基金supported by the National Natural Science Foundation of China(Grant Nos.61378036,61307058,11304101,11074078,and 11474108)the Ph D Start-Up Fund of the Natural Science Foundation of Guangdong Province,China(Grant No.S2013040016320)+2 种基金the Scientific Research Foundation of the Graduate School of South China Normal University,China(Grant No.2014bsxm06)the Zhujiang New-Star Plan of Science and Technology in Guangzhou City(Grant No.2014J2200008)the Open Fund of the Guangdong Provincial Key Laboratory of Fiber Laser Materials and Applied Techniques(South China University of Technology)
文摘We report on the generation of Q-switched and Q-switched mode-locked （QML） pulses in an erbium-doped fiber ring laser by using a polyvinyl alcohol （PVA） -based gold nanorod （GNR） saturable absorber （SA）. The PVA- based GNR SA has a modulation depth of -4.8% and a non-saturable loss of -26.9% at 1.5 μm. A Q-switched pulse train with a repetition rate varying from 18.70 to 39.85 kHz and a QML pulse train with an envelope repetition rate tuning from 20.31 to 31.50 kHz are obtained. Moreover, the lasing wavelengths of the Q-switched pulses can be flexibly tuned by introducing a narrow bandwidth, tunable filter into the laser cavity. The results demonstrate that the GNRs exhibit good optical performance and can find a wide range of applications in the field of laser technology.
基金This work was supported by the Fujian Science Foundation for Facilitating Young Researcher's Innovation (No.2004J040)the Fujian Science Foundation on Suecial or Important Issue (No.2004H201).
文摘A new technique for seed-injection locking of single-axial-mode （SAM） Q-switched Nd：YAG laser is reported. The technique called energy reduction （ER） is utilized when SAM operation is locked to design its feedback scheme. This method ensures long-term 100% seed-injection locking performance and the pulsed SAM output energy can reach as high as 200 mJ. Both temporal and spatial interferometric experiments have been executed to confirm the SAM oscillation.
基金partly supported by the National Natural Science Foundation of China(No.61205130)the National Key Basic Research Program of China(No.2013CB922402)the National Key Scientific Instruments Development Program of China(No.2012YQ120047)
文摘We experimentally demonstrate a femtosecond optical parametric oscillator （OPO） synchronously pmnped by a home-made solid-state mode-locking Yb：YCOB laser, which is capable of laser pulse as short as 102 fs and average power of 620 mW at the central wavelength of 1052 nm. By using a periodically poled lithium niobate with tuning of the grating periods from 28.5 to 31.5μm as the nonlinear gain crystal, tunable femtosecond pulses from 1444 to 1683 nm are realized by conveniently adjusting the OPO cavity length with 76.8 MHz repetition rate. The maximum average output power is 152 mW at 1568 nm, corresponding to an idler power of 75 mW at 3197 nm as well as 36.6% total extraction efficiency.
基金National Key Research and Development Program of China(2023YFF0715802)National Natural Science Foundation of China(62305299,62205296 and12475006)+1 种基金Natural Science Foundation of Zhejiang Province(Z24F050008,LQ23F050004,LQ22F050007)Natural Science Basic Research Program of Shaanxi(2023-JC-YB-563)。
文摘Mode-locked fiber lasers are excellent platforms for soliton generation.Solitons exhibit distinct distribution and evolution characteristics depending on the net dispersion of the laser cavity.Here we propose an experimental scheme to reconstruct the intracavity dynamics of solitons within a mode-locked fiber laser.The proposed scheme is facilitated by disposing multiple output ports at different positions throughout the cavity,thereby enabling indepth observation and manipulation of soliton evolution along the dispersion map.The experimental results verify corresponding simulations and explain some phenomena from the perspective of soliton evolution.Our results offer a pathway for comprehensive analyses of intracavity pulse dynamics,fostering advancements in nonlinear and ultrafast optics.
基金supported by the National Key Research and Development Program of China(2022YFC2203902)the National Natural Science Foundation of China(No.62335009)+2 种基金the Interdisciplinary Research Program of Hust(2023JCYJ041)the Key Research and Development Program of Ningbo(No.2024T007)Wuhan Knowledge Innovation Special Project(2023010201010052).
文摘Polygonal optical vortices—a new subset of optical vortices—uniquely enable numerous applications due to the new degrees of freedom offered and their customizable light intensity structure.So far,their generation has only been reported for continuous wave.Here,we demonstrate the first femtosecond polygonal optical vortex pulses,which is also the first pulsed demonstration of such vortices in general.From a mode-locked Yb:KGW laser oscillator,femtosecond Hermit-Gaussian pulses at the quasi-frequency-degenerate state were generated and subsequently converted by astigmatic mode conversion to femtosecond polygonal optical vortices.They have light intensity distributions of square,pentagonal,and hexagonal shapes and carry orbital angular momentums.In all these variations,the average power and pulse duration are greater than one watt and less than 500 fs.These results open the way to new applications in the fields of femtosecond optical tweezer and three-dimensional microstructure fabrication.
基金supported by the National Natural Science Foundation of China(Grant No.62375275 and 62275254)by Strategic Priority Research Program of the Chinese Academy of Science(XDB0650000)+1 种基金by Shanghai Science and Technology Plan Project Funding(Grant No.23JC1410100)by Fuyang High-level Talent Group Project.
文摘Harmonic mode-locking,realized actively or passively,is an effective technique for increasing the repetition rate of ultrafast lasers.It is critically important to understand how a harmonically mode-locked pulse train responds to external perturbations and noise,so as to make sure that it is stable and resistant to noise.Here,in a series of carefully designed experiments,we elucidate the retiming dynamics of laser pulses generated in a soliton fiber laser harmonically modelocked at GHz frequencies to the acoustic resonance in a photonic crystal fiber(PCF)core.We characterize the selfdriven optomechanical lattice,which is distributed along the PCF and provides the structure that supports harmonic mode-locking,using a homodyne setup.We reveal that,after an abrupt perturbation,each soliton in the lattice undergoes damped oscillatory retiming within its trapping potential,while the retiming is strongly coupled to soliton dissipation.In addition,we show,through statistical analysis of the intra-cavity pulse spacing,how the trapping potentials are effective for suppressing timing jtter.The measurements and the theory developed in this work lay the groundwork for studies of the general stability and noise performance of harmonically mode-locked lasers as well as providing valuable insight into generic multi-pulse phenomena in mode-locked lasers.
基金National Natural Science Foundation of China(12274238, 62205159, 61835006)Special Project for Cooperation in Basic Research of Beijing,Tianjin and Hebei (21JCZXJC00010)
文摘The complexity of multi-dimensional optical wave dynamics arises from the introduction of multiple degrees of freedom and their intricate interactions.In comparison to multimode spatiotemporal mode-locked solitons,expanding the wavelength dimension is also crucial for studying the dynamics of multi-dimensional solitons,with simpler characterization techniques。
文摘We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of -230 MHz was achieved and the pulse train was modulated by the Q-switched envelope with the repetition rate of -150 kHz. The maximum output of 4 W was obtained under the pump power of 13.5 W. The optical-to-optical efficiency was 30%. We also discussed the transition of each process having emerged.
基金This work was supported in part by the National "863"project of China under Grant No. 2002AA311190China Ministry of Science and technology.
文摘We report a diode end-pumped continuous wave (CW) passively mode-locked Nd:YVO4 laser with a homemade semiconductor saturable absorber mirror (SESAM). The maximum average output power is 5.3 W at the incident pump power of 17 W, which corresponds to an optical-optical conversion efficiency of 31.2% and slope efficiency of 34.7%. The corresponding optical spectrum has a 0.2-nm full width at half maximum (FWHM). and the pulse repetition rate is 83 MHz.
基金This work was supported by the National Natural Science Foundation of China (No. 60477022) the Project of Tianjin United Institute of Optoelectronics (No. 033800411).
文摘A 10-GHz soliton source with pulse duration between 4-8 ps and wavelength continuously tunable from 1530 nm to 1563 nm is presented. Using regeneratively mode-locking technology, the harmonically mode-locked fiber ring laser could work without pulse dropout at room temperature when no cavity length or polarization maintaining mechanism is available. Applying only one 980-nm laser diode pump, the average output power reaches more than 4 mW.
基金This work was supported by the Doctoral Programme Foundation of the Institution of Higher Education of China (No. 1999005615) and the National Natural Science Foundation of China (No. 69877012).
文摘The nonlinear optical loop mirror (NOLM) is used as a saturable absorbed to reshape pulses. Experimentally, an actively mode-locked erbium-doped fiber ring laser with figure-eight structure is set up. 2 - 4 order harmonic pulse train with stable amplitude has been obtained when the RF modulation frequency is about 2.5 GHz.
基金This work was supported by the Beijing elitist fund and Ph. D. fund from Beijing University of Technology.
文摘A diode-pumped Yb3+:YAl3(BO3)3 (Yb:YAB) laser system was demonstrated with continuous wave (CW) and pulsed output. The polarized CW outputs and femtosecond mode-locked lasers with semiconductor saturable-absorber mirrors (SESAM) at the fundamental wavelength were measured. For the CW output, polarization ratios were 88.1% (for e-ray) and 87.2% (for o-ray). For the mode-locked system, polarization ratio reached 38.5%, and the repetition frequency was 117.6 MHz.
基金This work was supported by the National Natural Science Foundation of China (No. 60578043) and Beijing Education Committee Common Build Foundation (No. XK100130537)
文摘A wavelength tunable, high repetition rate mode-locked fiber ring laser was demonstrated. In the experiment, photonic crystal fiber （PCF） is used as an intracavity compression medium. The high nonlinearity and anomalous dispersion of PCF can cause intracavity compression and result in significant reduction in the pulse width. The pulses duration at the repetition rate of 9.99 GHz was less than 10 ps over the range of 1532-1565 nm.
基金This work was supported by the National Natural Science Foundation(No.10525416 and 60478011)National Key Project for Basic Research(No.2006CB806000)+2 种基金Key Projects from Science and Technology Commission of Shanghai Municipality(No.04dz14001 and 06JC14025)Program for Changjiang Scholars and Innovative Researeh Team(PCSIRT)One of the authors(J.Wu)thanks the support of the Research Program from the Graduate School of ECNU
文摘Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.
基金This work was supported by the National Natural Science Foundation of China under Grant No. 60478009.
文摘A diode-pumped passively Q-switched Nd：YLF laser was demonstrated by using saturable absorber of Cr^4＋：YAG. At the incident power of 7.74 W, pure passively Q-switched laser with per pulse energy of 210 μJ and pulse width of 19.6 ns at repetition rate of 1.78 kHz was obtained by using Cr^4＋：YAG with initial transmission of 80%. At the incident power of 8.70 W, a Q-switched mode-locking with average output power of 650 mW was achieved, the overall slop efficiency was 16%, corresponding to the initial transmission of 85% of Cr^4＋ ：YAG.
基金supported by the Fundamental Research Funds for the Central Universities (Grant Nos. 3102014JCQ01101, 3102014JCQ01099, and 3102014JCQ01085)the 973 Program (Grant No. 2012CB921900)the National Natural Science Foundation of China (Grant Nos. 61405161, 11404263, and 61377035)
文摘We propose a low-threshold soliton fiber laser passively mode locked with two different types of film-like saturable absorbers, one of which is fabricated by mixing Bi2Te3 with de-ionized water, as well as polyvinyl alcohol（PVA）, and then evaporating them in a Petri dish, and the other of which is prepared by directly dropping Bi2Te3 solution on the PVA film. Both Bi2Te3–PVA films exhibit outstanding features of low loss, high flexibility, and easy synthesis. By incorporating Bi2Te3–PVA films into fiber lasers, stable single-soliton emissions are obtained at a low pump power of 13 mW. Our results suggest that the Bi2Te3 can work as a promising mode locker for ultrafast lasers,while PVA is an excellent host for fabricating high-performance film-based saturable absorbers.
文摘A frequency-stabilized laser system at 1572 nm for space-borne carbon dioxide （CO2） detection LIDAR to realize the precise measurement of the global atmospheric CO2 concentration is presented in this Letter. A distributed- feedback laser diode serves as the master laser （ML） and is wavelength locked to the CO2 line center at 1572.0179 nm using the external frequency modulation technique. The root mean square frequency drift is sup- pressed to about 50 kHz at an average time of 0.1 s over 8 h. Based on optical phase-locked loops, an online seeder and an offiine seeder are offset locked to the reference laser at 1572.024 and 1572.081 nm, respectively, retaining virtually the same frequency stability as the ML.
基金supported by the National High-Tech Research and Development ("863") Program of China (No.2006AA03Z348)the Key Program of Science and Technology Research of Shanghai Education Commission (No.10ZZ94)+1 种基金the Shanghai Leading Academic Discipline Project (No.S30502)the Shanghai Talents Developing Foundation (No.014)
文摘An optimized dual fiber Bragg grating （FBG） is proposed for 980-nm semiconductor lasers without thermoelectric coolers to restrict temperature-induced wavelength shift.The mathematical model of the temperature-induced wavelength shift of the laser with the dual FBG is built using the external cavity feedback rate equations.The external cavity parameters are optimized for achieving the stability mode-locking laser output.The spectral characteristics of the dual FBG stabilized laser are measured to range from 0 to 70 °C.The side mode suppression ratio （SMSR） is more than 45 dB,while the full-width at half-maximum （FWHM） is less than 1 nm.The peak wavelength shift is less than 0.1 nm.The dual FBG wavelength shift proportional coefficient is between 0.1086 and 0.4342.
