Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory.Kinesin-4 KIF21A helps organize the microtubule-actin network at th...Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory.Kinesin-4 KIF21A helps organize the microtubule-actin network at the cell cortex by interacting with KANK1;however,whether KIF21A modulates dendritic structure and function in neurons remains unknown.In this study,we found that KIF21A was distributed in a subset of dendritic spines,and that these KIF21A-positive spines were larger and more structurally plastic than KIF21A-negative spines.Furthermore,the interaction between KIF21A and KANK1 was found to be critical for dendritic spine morphogenesis and synaptic plasticity.Knockdown of either KIF21A or KANK1 inhibited dendritic spine morphogenesis and dendritic branching,and these deficits were fully rescued by coexpressing full-length KIF21A or KANK1,but not by proteins with mutations disrupting direct binding between KIF21A and KANK1 or binding between KANK1 and talin1.Knocking down KIF21A in the hippocampus of rats inhibited the amplitudes of long-term potentiation induced by high-frequency stimulation and negatively impacted the animals’cognitive abilities.Taken together,our findings demonstrate the function of KIF21A in modulating spine morphology and provide insight into its role in synaptic function.展开更多
Optical frequency combs,as powerful tools for precision spectroscopy and research into optical frequency standards,have driven continuous progress and significant breakthroughs in applications such as time-frequency t...Optical frequency combs,as powerful tools for precision spectroscopy and research into optical frequency standards,have driven continuous progress and significant breakthroughs in applications such as time-frequency transfer,measurement of fundamental physical constants,and high-precision ranging,achieving a series of milestone results in ground-based environments.With the continuous maturation and evolution of femtosecond lasers and related technologies,optical frequency combs are moving from ground-based applications to astronomical and space-based applications,playing an increasingly important role in atomic clocks,exoplanet observations,gravitational wave measurements,and other areas.This paper,focusing on astronomical and space-based applications,reviews research progress on astronomical frequency combs,optical clock time-frequency networks,gravitational waves,dark matter measurement,dual-comb large-scale absolute ranging,and high-resolution atmospheric spectroscopy.With enhanced performance and their gradual application in the field of space-based research,optical frequency combs will undoubtedly provide more powerful support for astronomical science and cosmic exploration in the future.展开更多
The persistent increase of CO_(2) levels in the atmosphere,already exceeding 400 ppm,urges the exploration of CO_(2) emission reduction and recycling technologies.Ideally,photocatalytic conversion of CO_(2) into valua...The persistent increase of CO_(2) levels in the atmosphere,already exceeding 400 ppm,urges the exploration of CO_(2) emission reduction and recycling technologies.Ideally,photocatalytic conversion of CO_(2) into valuable hydrocarbons realizes solar-to-chemical energy conversion,which is a desirable“kill two birds with one stone”strategy;namely,CO_(2) photoreduction can simultaneously tackle energy shortage and keep global carbon balance.Graphitic carbon nitride(g-C_(3)N_(4))working on CO_(2) reduction reaction deserves a highlight not only for the metal-free feature that endows it with low cost,tunable electronic structure,and easy fabrication properties but also because of its strong reduction ability.The present review concisely summarizes the latest advances of g-C_(3)N_(4)-based photocatalysts toward CO_(2) reduction.It starts with the discussion of thermodynamics and dynamics aspects of the CO_(2) reduction process.Then the modification strategies to promote g-C_(3)N_(4)-based photocatalysts in CO_(2) photoreduction have been discussed in detail,including surface functionalization,molecule structure engineering,crystallization,morphology engineering,loading cocatalyst,and constructing heterojunction.Meanwhile,the intrinsic factors affecting CO_(2) reduction activity and selectivity are analyzed and summarized.In the end,the challenges and prospects for the future development of highly g-C_(3)N_(4)-based photocatalysts in CO_(2) reduction are also presented.展开更多
Q-switched lasers have occupied important roles in industrial applications such as laser marking,engraving,welding,and cutting due to their advantages in high pulse energy.Here,SnS_(2)-based Q-switched lasers are impl...Q-switched lasers have occupied important roles in industrial applications such as laser marking,engraving,welding,and cutting due to their advantages in high pulse energy.Here,SnS_(2)-based Q-switched lasers are implemented.Consid-ering that SnS_(2) inherits the thickness sensitive optical characteristics of TMD,three kinds of SnS2 with different thick-ness are characterized in terms of nonlinearity and used to realize the Q-switched pulses under consistent implementa-tion conditions for comparison tests.According to the results,the influence of thickness variation on the nonlinear per-formance of saturable absorber,such as modulation depth and absorption intensity,and the influence on the correspond-ing laser are analyzed.In addition,compared with other traditional saturable absorbers,the advantage of SnS_(2) in realiz-ing ultrashort pulses is also noticed.Our work explores the thickness-dependent nonlinear optical properties of SnS_(2),and the rules found is of great reference value for the establishment of target lasers.展开更多
We report a direct blue-diode-pumped wavelength tunable Kerr-lens mode-locked Ti: sapphire laser.Central wavelength tunability as broad as 89 nm(736-825 nm) is achieved by adjusting the insertion of the prism.Pulses a...We report a direct blue-diode-pumped wavelength tunable Kerr-lens mode-locked Ti: sapphire laser.Central wavelength tunability as broad as 89 nm(736-825 nm) is achieved by adjusting the insertion of the prism.Pulses as short as 17 fs are generated at a central wavelength of 736 nm with an average output power of 31 mW.The maximum output power is 46.8 mW at a central wavelength of 797 nm with a pulse duration of 46 fs.展开更多
Wide bandgap semiconductors play more and more important roles in both scientific researches and industrial applications.The unique wide bandgap properties provide a platform for flexible functional design for crystal...Wide bandgap semiconductors play more and more important roles in both scientific researches and industrial applications.The unique wide bandgap properties provide a platform for flexible functional design for crystal growth,defect engineering,interface engineering,and device construction.Meanwhile,the underlying physical展开更多
Stable 68 fs pulses with the average power of 1.5 W is directly generated from a multimode diode-pumped Kerr-lens mode-locked Yb:CYA laser by separating the gain medium and Kerr medium. The repetition rate is about 50...Stable 68 fs pulses with the average power of 1.5 W is directly generated from a multimode diode-pumped Kerr-lens mode-locked Yb:CYA laser by separating the gain medium and Kerr medium. The repetition rate is about 50 MHz, resulting in a single pulse energy of 30 n J and a peak power of 0.44 MW. To the best of our knowledge, this is the highest single pulse energy ever produced from a mode-locked Yb:CYA oscillator. Our experimental results show that Yb:CYA crystal is an excellent candidate for multiwatt, sub-100 fs pulse generation in diode-pumped all-solid-state lasers. It is believed that the output power can be scalable to multi-W while the pulse duration is maintained with this simple method.展开更多
We experimentally demonstrated a diode-pumped Kerr-lens mode-locked femtosecond laser with a Yb:CaYAlO4 crystal as the gain medium. Pulse duration as short as 33 fs was obtained directly from the oscillator at a repet...We experimentally demonstrated a diode-pumped Kerr-lens mode-locked femtosecond laser with a Yb:CaYAlO4 crystal as the gain medium. Pulse duration as short as 33 fs was obtained directly from the oscillator at a repetition rate of 115 MHz. The central wavelength was at 1059 nm with a spectral bandwidth of 49 nm. These are, to the bestof our knowledge, the shortest pulses generated from a Yb:CaYAlO4 oscillator.展开更多
Two-dimensional(2D) materials with potential applications in photonic and optoelectronic devices have attracted increasing attention due to their unique structures and captivating properties. However, generation of st...Two-dimensional(2D) materials with potential applications in photonic and optoelectronic devices have attracted increasing attention due to their unique structures and captivating properties. However, generation of stable high-energy ultrashort pulses requires further boosting of these materials' optical properties, such as higher damage threshold and larger modulation depth. Here we investigate a new type of heterostructure material with uniformity by employing the magnetron sputtering technique. Heterostructure materials are synthesized with van der Waals heterostructures consisting of MoS_2 and Sb_2Te_3. The bandgap, carrier mobility, and carrier concentration of the MoS_2-Sb_2Te_3-MoS_2 heterostructure materials are calculated theoretically. By using these materials as saturable absorbers(SAs), applications in fiber lasers with Q-switching and mode-locking states are demonstrated experimentally. The modulation depth and damage threshold of SAs are measured to be 64.17%and 14.13 J∕cm^2, respectively. Both theoretical and experimental results indicate that MoS_2-Sb_2Te_3-MoS_2 heterostructure materials have large modulation depth, and can resist high power during the generation of ultrashort pulses. The MoS_2-Sb_2Te_3-MoS_2 heterostructure materials have the advantages of low cost, high reliability, and suitability for mass production, and provide a promising solution for the development of 2D-material-based devices with desirable electronic and optoelectronic properties.展开更多
Tungsten disulfide(WS_2) is a type of anisotropic-layered compound and has broadband saturable absorption features as saturable absorbers(SAs). With WS_2-based SAs, dark solitons in erbium-doped fiber(EDF) lasers are ...Tungsten disulfide(WS_2) is a type of anisotropic-layered compound and has broadband saturable absorption features as saturable absorbers(SAs). With WS_2-based SAs, dark solitons in erbium-doped fiber(EDF) lasers are first obtained. For the generated dark solitons, the center wavelength is measured to be 1530 nm, and the repetition rate is about 116.5 MHz. A series of optical spectra is exhibited. The electrical signal-to-noise ratio is better than 94 d B.Results in this paper demonstrate that WS_2-based SAs are the promising SAs for generating dark solitons in EDF lasers.展开更多
Transition metal dichalcogenides(TMDs) are successfully applied in fiber lasers for their photoelectric properties.However, in previous work, how to improve the modulation depth of TMD-based saturable absorbers(SAs) h...Transition metal dichalcogenides(TMDs) are successfully applied in fiber lasers for their photoelectric properties.However, in previous work, how to improve the modulation depth of TMD-based saturable absorbers(SAs) has been a challenging issue. In this paper, WSe_2 and MoSe_2 SAs are fabricated with the chemical vapor deposition method. Compared with previous experiments, the modulation depths of WSe_2 and MoSe_2 SAs with sandwiched structures are effectively increased to 31.25% and 25.69%, respectively. The all-fiber passively Q-switched erbium doped fiber lasers based on WSe_2 and MoSe_2 SAs are demonstrated. The signal-to-noise ratios of those lasers are measured to be 72 and 57 dB, respectively. Results indicate that the proposed WSe_2 and MoSe_2 SAs are efficient photonic devices to realize stable fiber lasers.展开更多
We report on the study of single-mode fiber-laser-pumped mode-locked Yb:CALYO lasers via using a passive saturable absorber and Kerr-lens mode-locking technique,respectively.Up to 3.1-W average power with 103-fs pulse...We report on the study of single-mode fiber-laser-pumped mode-locked Yb:CALYO lasers via using a passive saturable absorber and Kerr-lens mode-locking technique,respectively.Up to 3.1-W average power with 103-fs pulse duration is obtained from the passive mode-locking,and down to 36-fs pulse duration with more than 2-W average power is achieved by the pure Kerr-lens mode-locking,which is to the best of our knowledge,the highest average power from a reported sub-40-fs Yb-based solid-state oscillator.展开更多
We demonstrate a diode-pumped femtosecond Yb:CaGdAlO_(4)(Yb:CALGO)laser with a semiconductor saturable absorber mirror(SESAM)for stable mode-locking operation.A perfect beam profile is measured under 10 W output power...We demonstrate a diode-pumped femtosecond Yb:CaGdAlO_(4)(Yb:CALGO)laser with a semiconductor saturable absorber mirror(SESAM)for stable mode-locking operation.A perfect beam profile is measured under 10 W output power with M_(x)^(2)=1.017 and M_(y)^(2)=1.016 in the horizontal and vertical directions,respectively.At the repetition rate of 71.66 MHz,the optical pulse duration is 247 fs and the pulse energy is 140 nJ at the central wavelength of 1041 nm,corresponding to a peak power of 0.56 MW.In addition,we also generate continuous wave(CW)power of more than 15 W with TEM00 mode,corresponding to an optical-to-optical efficiency of 44.1%.展开更多
We report Q-switched and mode-locked erbium-doped all-fiber lasers using ternary ReS_(2(1-x))Se_(2x) as saturable absorbers(SAs). The modulation depth and saturable intensity of the film SA are 1.8% and 0.046 MW∕cm2....We report Q-switched and mode-locked erbium-doped all-fiber lasers using ternary ReS_(2(1-x))Se_(2x) as saturable absorbers(SAs). The modulation depth and saturable intensity of the film SA are 1.8% and 0.046 MW∕cm2.In Q-switched mechanism output, the pulse was centered at 1531.1 nm with maximum pulse energy and minimum pulse width of 28.29 nJ and 1.07 μs, respectively. In mode-locked operation, the pulse was centered at1561.15 nm with pulse width of 888 fs, repetition rate of 2.95 MHz, and maximum pulse energy of 0.275 nJ. To the best of our knowledge, this is the first report on the mode-locked Er^(3+)-doped fiber laser using ternary transition metal dichalcogenides. This work suggests prospective 2 D-material SAs can be widely used in versatile fields due to their attractive optoelectronic and tunable energy bandgap properties.展开更多
By inversing the signal and idler in a two-stage noncollinear optical parametric amplifier which is,respectively,pumped by the second harmonic and fundamental wave of femtosecond Ti:sapphire laser at repetition rate o...By inversing the signal and idler in a two-stage noncollinear optical parametric amplifier which is,respectively,pumped by the second harmonic and fundamental wave of femtosecond Ti:sapphire laser at repetition rate of1 kHz,the carrier-envelope phase(CEP)passively stabilized pulses with a tunable wavelength from 1.1 to 1.6 lm are obtained with maximum energy of 95 lJ at 1.3 lm under the pump energy of 500 lJ.The CEP jitter of pulses is 108 mrad measured by an f-2f interferometer.This work demonstrates a new way to efficiently generate tunable near-infrared femtosecond laser pulses with self-stabilized CEP.展开更多
Compared with the extensively studied MoS2 and WS2, WTe_2 owns a smaller bandgap, which is applicable to a near-infrared system in photodetectors, communications, and ultrafast optics. In this work, the WTe_2 saturabl...Compared with the extensively studied MoS2 and WS2, WTe_2 owns a smaller bandgap, which is applicable to a near-infrared system in photodetectors, communications, and ultrafast optics. In this work, the WTe_2 saturable absorber(SA) with the tapered fiber structure is prepared by the magnetron-sputtering technology, which enables the prepared SA to be low in cost and have strong nonlinearity. The modulation depth of the prepared WTe_2 SA is measured as 31.06%. The Q-switched fiber laser operating at 1.5 μm is successfully investigated by incorporating the proposed SA into the prepared ring cavity. To the best of our knowledge, this is the first attempt of WTe_2 in the Q-switched fiber laser at 1.5 μm.展开更多
High harmonic generation(HHG)delivering attosecond pulse duration with photon energy in the extreme ultraviolet spectral range has been demonstrated as a robust table-top coherent light source,allowing for the observa...High harmonic generation(HHG)delivering attosecond pulse duration with photon energy in the extreme ultraviolet spectral range has been demonstrated as a robust table-top coherent light source,allowing for the observation and manipulation of ultrafast process within the shortest time window ever made by humans.The past decade has witnessed the rapid progress of HHG from a variety of solid targets and its application for photoemission spectroscopy in condensed matter.In this article,we review the HHG in solids and the understanding of the underlying physics of HHG,which allows all-optical band structure reconstruction.We also introduce combinations of HHG source and photoemission spectroscopy,such as angular-resolved photoemission spectroscopy and photoemission electron microscopy.With the capacity of exploring a wide momentum space and high temporal resolution,the extension of attosecond science to the field of condensed matter physics will lead to new insights into the fundamental ultrafast dynamics in novel quantum materials.展开更多
基金supported by the National Key Research and Development Program of China,No.2021ZD0202503(to AHT)the National Natural Science Foundation of China,Nos.31872759(to AHT)and 32070707(to CF)+1 种基金Shenzhen Science and Technology Program,No.RCJC20210609104333007(to ZW)Shenzhen-Hong Kong Institute of Brain Science,Shenzhen Fundamental Research Institutions,No.2021SHIBS0002(to ZW).
文摘Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and memory.Kinesin-4 KIF21A helps organize the microtubule-actin network at the cell cortex by interacting with KANK1;however,whether KIF21A modulates dendritic structure and function in neurons remains unknown.In this study,we found that KIF21A was distributed in a subset of dendritic spines,and that these KIF21A-positive spines were larger and more structurally plastic than KIF21A-negative spines.Furthermore,the interaction between KIF21A and KANK1 was found to be critical for dendritic spine morphogenesis and synaptic plasticity.Knockdown of either KIF21A or KANK1 inhibited dendritic spine morphogenesis and dendritic branching,and these deficits were fully rescued by coexpressing full-length KIF21A or KANK1,but not by proteins with mutations disrupting direct binding between KIF21A and KANK1 or binding between KANK1 and talin1.Knocking down KIF21A in the hippocampus of rats inhibited the amplitudes of long-term potentiation induced by high-frequency stimulation and negatively impacted the animals’cognitive abilities.Taken together,our findings demonstrate the function of KIF21A in modulating spine morphology and provide insight into its role in synaptic function.
基金support of the National Natural Sci-ence Foundation of China(NSFC)(62305373)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA1502040404,XDB2101040004).
文摘Optical frequency combs,as powerful tools for precision spectroscopy and research into optical frequency standards,have driven continuous progress and significant breakthroughs in applications such as time-frequency transfer,measurement of fundamental physical constants,and high-precision ranging,achieving a series of milestone results in ground-based environments.With the continuous maturation and evolution of femtosecond lasers and related technologies,optical frequency combs are moving from ground-based applications to astronomical and space-based applications,playing an increasingly important role in atomic clocks,exoplanet observations,gravitational wave measurements,and other areas.This paper,focusing on astronomical and space-based applications,reviews research progress on astronomical frequency combs,optical clock time-frequency networks,gravitational waves,dark matter measurement,dual-comb large-scale absolute ranging,and high-resolution atmospheric spectroscopy.With enhanced performance and their gradual application in the field of space-based research,optical frequency combs will undoubtedly provide more powerful support for astronomical science and cosmic exploration in the future.
基金Natural Science Foundation of Xinjiang Province,Grant/Award Numbers:2019D01C064,2020D01A49,2020D01B25,2021D01B40National Natural Science Foundation of China,Grant/Award Numbers:21905209,52072273Tianshan innovation team project of Xinjiang Uygur Autonomous Region,Grant/Award Number:2021D14013。
文摘The persistent increase of CO_(2) levels in the atmosphere,already exceeding 400 ppm,urges the exploration of CO_(2) emission reduction and recycling technologies.Ideally,photocatalytic conversion of CO_(2) into valuable hydrocarbons realizes solar-to-chemical energy conversion,which is a desirable“kill two birds with one stone”strategy;namely,CO_(2) photoreduction can simultaneously tackle energy shortage and keep global carbon balance.Graphitic carbon nitride(g-C_(3)N_(4))working on CO_(2) reduction reaction deserves a highlight not only for the metal-free feature that endows it with low cost,tunable electronic structure,and easy fabrication properties but also because of its strong reduction ability.The present review concisely summarizes the latest advances of g-C_(3)N_(4)-based photocatalysts toward CO_(2) reduction.It starts with the discussion of thermodynamics and dynamics aspects of the CO_(2) reduction process.Then the modification strategies to promote g-C_(3)N_(4)-based photocatalysts in CO_(2) photoreduction have been discussed in detail,including surface functionalization,molecule structure engineering,crystallization,morphology engineering,loading cocatalyst,and constructing heterojunction.Meanwhile,the intrinsic factors affecting CO_(2) reduction activity and selectivity are analyzed and summarized.In the end,the challenges and prospects for the future development of highly g-C_(3)N_(4)-based photocatalysts in CO_(2) reduction are also presented.
基金the financial support from the National Natural Science Foundation of China(11875008,12075034)Open Research Fund of State Key Laboratory of Pulsed Power Laser Technology(Grant SKL2019KF04)Fundamental Research Funds for the Central Universities(2019XD-A09-3).
文摘Q-switched lasers have occupied important roles in industrial applications such as laser marking,engraving,welding,and cutting due to their advantages in high pulse energy.Here,SnS_(2)-based Q-switched lasers are implemented.Consid-ering that SnS_(2) inherits the thickness sensitive optical characteristics of TMD,three kinds of SnS2 with different thick-ness are characterized in terms of nonlinearity and used to realize the Q-switched pulses under consistent implementa-tion conditions for comparison tests.According to the results,the influence of thickness variation on the nonlinear per-formance of saturable absorber,such as modulation depth and absorption intensity,and the influence on the correspond-ing laser are analyzed.In addition,compared with other traditional saturable absorbers,the advantage of SnS_(2) in realiz-ing ultrashort pulses is also noticed.Our work explores the thickness-dependent nonlinear optical properties of SnS_(2),and the rules found is of great reference value for the establishment of target lasers.
基金Project supported by the National Key R&D Program of China(Grant No.2016YFB0402105)
文摘We report a direct blue-diode-pumped wavelength tunable Kerr-lens mode-locked Ti: sapphire laser.Central wavelength tunability as broad as 89 nm(736-825 nm) is achieved by adjusting the insertion of the prism.Pulses as short as 17 fs are generated at a central wavelength of 736 nm with an average output power of 31 mW.The maximum output power is 46.8 mW at a central wavelength of 797 nm with a pulse duration of 46 fs.
基金partly supported by the National Key Technology R&D Program of the Ministry of Science and Technology(2012BAC23B03)+2 种基金 National Key Basic Research Program of China(2013CB922401) the National Natural Science Foundation of China(11074298,60878020)
文摘Wide bandgap semiconductors play more and more important roles in both scientific researches and industrial applications.The unique wide bandgap properties provide a platform for flexible functional design for crystal growth,defect engineering,interface engineering,and device construction.Meanwhile,the underlying physical
基金National Key Basic Research Program of China(2013CB922402)National Natural Science Foundation of China(NSFC)(61705174,11774277)+2 种基金Fundamental Research Funds for the Central Universities(JBX170511)Open Fund of IPOC(BUPT)(IPOC2016B009)111 Project(B17035)
文摘Stable 68 fs pulses with the average power of 1.5 W is directly generated from a multimode diode-pumped Kerr-lens mode-locked Yb:CYA laser by separating the gain medium and Kerr medium. The repetition rate is about 50 MHz, resulting in a single pulse energy of 30 n J and a peak power of 0.44 MW. To the best of our knowledge, this is the highest single pulse energy ever produced from a mode-locked Yb:CYA oscillator. Our experimental results show that Yb:CYA crystal is an excellent candidate for multiwatt, sub-100 fs pulse generation in diode-pumped all-solid-state lasers. It is believed that the output power can be scalable to multi-W while the pulse duration is maintained with this simple method.
基金supported by the National Major Scientific Instruments Development Project of China (Grant No. 2012YQ120047)the National Natural Science Foundation of China (Grant No. 61205130)
文摘We experimentally demonstrated a diode-pumped Kerr-lens mode-locked femtosecond laser with a Yb:CaYAlO4 crystal as the gain medium. Pulse duration as short as 33 fs was obtained directly from the oscillator at a repetition rate of 115 MHz. The central wavelength was at 1059 nm with a spectral bandwidth of 49 nm. These are, to the bestof our knowledge, the shortest pulses generated from a Yb:CaYAlO4 oscillator.
基金National Natural Science Foundation of China(NSFC)(11674036)Beijing University of Posts and Telecommunications(BUPT)(IPOC2016ZT04,IPOC2017ZZ05)+2 种基金Beijing Youth Top-Notch Talent Support Program(2017000026833ZK08)Special Program for Applied Research on Super Computation of the NSFC Guangdong Joint Fund(U1501501)XAFS Station(BL14W1)
文摘Two-dimensional(2D) materials with potential applications in photonic and optoelectronic devices have attracted increasing attention due to their unique structures and captivating properties. However, generation of stable high-energy ultrashort pulses requires further boosting of these materials' optical properties, such as higher damage threshold and larger modulation depth. Here we investigate a new type of heterostructure material with uniformity by employing the magnetron sputtering technique. Heterostructure materials are synthesized with van der Waals heterostructures consisting of MoS_2 and Sb_2Te_3. The bandgap, carrier mobility, and carrier concentration of the MoS_2-Sb_2Te_3-MoS_2 heterostructure materials are calculated theoretically. By using these materials as saturable absorbers(SAs), applications in fiber lasers with Q-switching and mode-locking states are demonstrated experimentally. The modulation depth and damage threshold of SAs are measured to be 64.17%and 14.13 J∕cm^2, respectively. Both theoretical and experimental results indicate that MoS_2-Sb_2Te_3-MoS_2 heterostructure materials have large modulation depth, and can resist high power during the generation of ultrashort pulses. The MoS_2-Sb_2Te_3-MoS_2 heterostructure materials have the advantages of low cost, high reliability, and suitability for mass production, and provide a promising solution for the development of 2D-material-based devices with desirable electronic and optoelectronic properties.
基金supported by the National Key Basic Research Program of China (grant nos.2012CB821304,2013CB922401,and 2013CB922402)by the National Natural Science Foundation of China (NSFC) (grant nos.61205064,61378040,and 11078022)+1 种基金by the National Key Technology R&D Program of the Ministry of Science and Technology under grant no.2012BAC23B03by the Fund of State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications,grant no.600100161)
文摘Tungsten disulfide(WS_2) is a type of anisotropic-layered compound and has broadband saturable absorption features as saturable absorbers(SAs). With WS_2-based SAs, dark solitons in erbium-doped fiber(EDF) lasers are first obtained. For the generated dark solitons, the center wavelength is measured to be 1530 nm, and the repetition rate is about 116.5 MHz. A series of optical spectra is exhibited. The electrical signal-to-noise ratio is better than 94 d B.Results in this paper demonstrate that WS_2-based SAs are the promising SAs for generating dark solitons in EDF lasers.
基金National Natural Science Foundation of China(NSFC)(11674036)Beijing Youth Top-Notch Talent Support Program(2017000026833ZK08)Beijing University of Posts and Telecommunications(BUPT)(IPOC2016ZT04,IPOC2017ZZ05)
文摘Transition metal dichalcogenides(TMDs) are successfully applied in fiber lasers for their photoelectric properties.However, in previous work, how to improve the modulation depth of TMD-based saturable absorbers(SAs) has been a challenging issue. In this paper, WSe_2 and MoSe_2 SAs are fabricated with the chemical vapor deposition method. Compared with previous experiments, the modulation depths of WSe_2 and MoSe_2 SAs with sandwiched structures are effectively increased to 31.25% and 25.69%, respectively. The all-fiber passively Q-switched erbium doped fiber lasers based on WSe_2 and MoSe_2 SAs are demonstrated. The signal-to-noise ratios of those lasers are measured to be 72 and 57 dB, respectively. Results indicate that the proposed WSe_2 and MoSe_2 SAs are efficient photonic devices to realize stable fiber lasers.
基金supported by the National Key Basic Research Program of China(No.2017YFB0405202)National Natural Science Foundation of China(NSFC)(Nos.61705174 and 11774277)+2 种基金Natural Science Basic Research Plan in Shaanxi Province of China(No.2018JQ6061)Open Research Fund of the State Key Laboratory of Pulsed Power Laser TechnologyElectronic Engineering Institute,Hefei,China(No.SKL2017KF04)。
文摘We report on the study of single-mode fiber-laser-pumped mode-locked Yb:CALYO lasers via using a passive saturable absorber and Kerr-lens mode-locking technique,respectively.Up to 3.1-W average power with 103-fs pulse duration is obtained from the passive mode-locking,and down to 36-fs pulse duration with more than 2-W average power is achieved by the pure Kerr-lens mode-locking,which is to the best of our knowledge,the highest average power from a reported sub-40-fs Yb-based solid-state oscillator.
基金the National Key R&D Program of China(No.2018YFB110720)the National Natural Science Foundation of China(Nos.61575217 and 91850209)the Strategic Priority Research Program of CAS(No.XDB16030200).
文摘We demonstrate a diode-pumped femtosecond Yb:CaGdAlO_(4)(Yb:CALGO)laser with a semiconductor saturable absorber mirror(SESAM)for stable mode-locking operation.A perfect beam profile is measured under 10 W output power with M_(x)^(2)=1.017 and M_(y)^(2)=1.016 in the horizontal and vertical directions,respectively.At the repetition rate of 71.66 MHz,the optical pulse duration is 247 fs and the pulse energy is 140 nJ at the central wavelength of 1041 nm,corresponding to a peak power of 0.56 MW.In addition,we also generate continuous wave(CW)power of more than 15 W with TEM00 mode,corresponding to an optical-to-optical efficiency of 44.1%.
基金National Key R&D Program of China(2018YFB1107200)National Natural Science Foundation of China(NSFC)(61675158,21673058)+1 种基金Chinese Academy of Sciences Key Project(CAS Key Project)(QYZDBSSW-SYS031)Chinese Academy of Sciences(CAS)(XDB30000000)
文摘We report Q-switched and mode-locked erbium-doped all-fiber lasers using ternary ReS_(2(1-x))Se_(2x) as saturable absorbers(SAs). The modulation depth and saturable intensity of the film SA are 1.8% and 0.046 MW∕cm2.In Q-switched mechanism output, the pulse was centered at 1531.1 nm with maximum pulse energy and minimum pulse width of 28.29 nJ and 1.07 μs, respectively. In mode-locked operation, the pulse was centered at1561.15 nm with pulse width of 888 fs, repetition rate of 2.95 MHz, and maximum pulse energy of 0.275 nJ. To the best of our knowledge, this is the first report on the mode-locked Er^(3+)-doped fiber laser using ternary transition metal dichalcogenides. This work suggests prospective 2 D-material SAs can be widely used in versatile fields due to their attractive optoelectronic and tunable energy bandgap properties.
基金partly supported by the National Key Technology R&D Program of the Ministry of Science and Technology(2012BAC23B03)National Key Basic Research Program of China(2013CB922401)the National Natural Science Foundation of China(11074298,60878020)
文摘By inversing the signal and idler in a two-stage noncollinear optical parametric amplifier which is,respectively,pumped by the second harmonic and fundamental wave of femtosecond Ti:sapphire laser at repetition rate of1 kHz,the carrier-envelope phase(CEP)passively stabilized pulses with a tunable wavelength from 1.1 to 1.6 lm are obtained with maximum energy of 95 lJ at 1.3 lm under the pump energy of 500 lJ.The CEP jitter of pulses is 108 mrad measured by an f-2f interferometer.This work demonstrates a new way to efficiently generate tunable near-infrared femtosecond laser pulses with self-stabilized CEP.
文摘Compared with the extensively studied MoS2 and WS2, WTe_2 owns a smaller bandgap, which is applicable to a near-infrared system in photodetectors, communications, and ultrafast optics. In this work, the WTe_2 saturable absorber(SA) with the tapered fiber structure is prepared by the magnetron-sputtering technology, which enables the prepared SA to be low in cost and have strong nonlinearity. The modulation depth of the prepared WTe_2 SA is measured as 31.06%. The Q-switched fiber laser operating at 1.5 μm is successfully investigated by incorporating the proposed SA into the prepared ring cavity. To the best of our knowledge, this is the first attempt of WTe_2 in the Q-switched fiber laser at 1.5 μm.
基金supported by the National Natural Science Foundation of China(Grant Nos.91850209,12174435 and 12034020)the National Key Research and Development Program of China(2017YFB0405202,2018YFB1107200).
文摘High harmonic generation(HHG)delivering attosecond pulse duration with photon energy in the extreme ultraviolet spectral range has been demonstrated as a robust table-top coherent light source,allowing for the observation and manipulation of ultrafast process within the shortest time window ever made by humans.The past decade has witnessed the rapid progress of HHG from a variety of solid targets and its application for photoemission spectroscopy in condensed matter.In this article,we review the HHG in solids and the understanding of the underlying physics of HHG,which allows all-optical band structure reconstruction.We also introduce combinations of HHG source and photoemission spectroscopy,such as angular-resolved photoemission spectroscopy and photoemission electron microscopy.With the capacity of exploring a wide momentum space and high temporal resolution,the extension of attosecond science to the field of condensed matter physics will lead to new insights into the fundamental ultrafast dynamics in novel quantum materials.