We integrally demonstrate 2μm mode-locked pulses performances in all-fiber net anomalous dispersion cavity.Stable mode-locking operations with the center wavelength around 1950–1980 nm can be achieved by using the n...We integrally demonstrate 2μm mode-locked pulses performances in all-fiber net anomalous dispersion cavity.Stable mode-locking operations with the center wavelength around 1950–1980 nm can be achieved by using the nonlinear polarization rotation structure and properly designing the dispersion management component.Conventional soliton is firstly obtained with a total anomalous dispersion cavity.Due to the contribution of commercial ultra-high numerical aperture fibers,net dispersion is reduced to-0.077 ps2.So that stretched pulse with 19.4 nm optical bandwidth is obtained and the de-chirped pulse-width can reach 312 fs using extra-cavity compression.Under pump power greater than 890 mW,stretched pulse can evolve into noise-like pulse with 41.3 nm bandwidth.The envelope and peak of such broadband pulse can be compressed with up to 2.2 ps and 145 fs,respectively.The single pulse energy of largely chirped stretched and noise-like pulse can reach 1.785 nJ and 1.53 nJ,respectively.Furthermore,extra-cavity compression can also contribute to a significant increase of peak power.展开更多
Coiled polymer artificial muscles with both large tensile stroke and giant force generation are needed for practical applications in robotics,soft exosuits,and prosthesis.However,most polymer yarn artificial muscles c...Coiled polymer artificial muscles with both large tensile stroke and giant force generation are needed for practical applications in robotics,soft exosuits,and prosthesis.However,most polymer yarn artificial muscles cannot generate a large force or stress.Here,we report an inexpensive Twisted and Coiled Polymer artificial muscle(TCP)that performs both large isobaric and isometric contractions.This TCP can generate a tensile stroke of 20.1%and a specific work capacity of up to 1.3 kJ kg^(−1) during temperature changes from 20 to 180℃.Moreover,the nylon yarn artificial muscle produced a reversible output stress of 28.4 MPa,which is 100 times larger than human skeletal muscle.A robot arm and a simple gripper were made to demonstrate the isobaric actuation and isometric actuation of our TCP muscle,repectivley.Thus,the polymer artificial muscles with dual-mode actuation show potential applications in the field of robotics,grippers,and exoskeletons and so on.展开更多
Recent years have seen significant advances in the study of dissipative soliton molecules in ultrafast lasers, driven by their remarkable connections to a wide range of physical systems. However, understanding and con...Recent years have seen significant advances in the study of dissipative soliton molecules in ultrafast lasers, driven by their remarkable connections to a wide range of physical systems. However, understanding and controlling the underlying physics of soliton molecules remain elusive due to the absence of a universal physical model that adequately describes intramolecular motion. We demonstrate that resonant excitation generates breather soliton molecules, with their resonance susceptibility exhibiting high amplitude-driven operations that can be well understood within the framework of the Duffing model. Harnessing powerful experiment techniques and detailed numerical simulations, we reveal the fundamental resonant mode within intrapulse separation constrained to the 100 fs level as well as the presence of the subharmonic and overtones. Additionally, we observe chaotic dynamics arising from the multiple-frequency nonlinear interactions in a strongly dissipative regime. Our work provides a perspective on the complex interactions of dissipative optical solitons through the lens of nonlinear physics. This approach offers a simple test bed for complex nonlinear physics research, with ultrafine scanning of temporal separations of ultrashort laser pulses demonstrating significant potential for applications requiring high detection sensitivity.展开更多
Soliton molecules in optical resonators have attracted remarkable attention in nonlinear dynamics,driven by their compelling analogies with matter molecules.So far,while extensive research has been conducted on their ...Soliton molecules in optical resonators have attracted remarkable attention in nonlinear dynamics,driven by their compelling analogies with matter molecules.So far,while extensive research has been conducted on their generation,pulsations,and dissociation behaviors,the investigation of their quasi-periodic dynamics has been relatively limited.Here,we present a systematic exploration of the quasi-periodic dynamics of soliton molecules using advanced balanced optical cross-correlation techniques.The incommensurable quasi-period bifurcations constituted of cascaded Hopf bifurcations are found,providing an unambiguous pathway toward chaotic soliton molecules.The chaotic intramolecular dynamics are analyzed by time series,radio frequency spectra,phase portraits,and Lyapunov exponent analysis.In addition,we reveal an intrinsic frequency entrainment phenomenon experimentally.Such frequency entrainment provides a novel perspective on synchronization in optical resonators,encompassing the competition and interaction of oscillations across multiple temporal scales.Our experimental findings offer clear proof that the gain dynamics serve as the origin of the binding forces between solitons within the molecule,which are well supported by the numerical simulations.By advancing the understanding of sub-femtosecond resolved quasi-period dynamics of optical soliton molecules,this study contributes to the broader field of complex nonlinear dynamics,paving the way for future explorations into the intricate behaviors of solitons within optical resonators and relevant fields.展开更多
Pulse duration is considered as one of the most important characteristics of high-power femtosecond lasers.However,pulses output from the laser system are susceptible to ambient changes and manifest the instability of...Pulse duration is considered as one of the most important characteristics of high-power femtosecond lasers.However,pulses output from the laser system are susceptible to ambient changes and manifest the instability of pulse durations in an open environment.In this paper,incorporating the algorithmic framework of the improved stochastic hill-climbing search and incremental proportional-integral controller,temperature-induced fluctuations of pulse duration can be effectively compensated by an automatic feedback control in an all-fiber chirped-pulse amplification system.In the experiment,sub-hundred femtosecond fluctuation of pulse duration is introduced to verify the performance robustness of the proposed pulse-duration feedback control(PDFC).The stability of pulse duration is obviously higher than the case without the feedback control,and the peak-to-peak fluctuation of pulse duration is reduced to 6.5%.Furthermore,the robust switching between different pulse durations proves the versatility of the PDFC.We expect that the proposed feedback control method could provide a novel insight into high-power femtosecond lasers widely applied in fundamental researches and industrial fields.展开更多
Recently, artificial intelligence has been proven as an effective modeling tool in ultrafast optics;its application in the design of ultrafast laser systems is a promising issue. In this Letter, a method based on a fe...Recently, artificial intelligence has been proven as an effective modeling tool in ultrafast optics;its application in the design of ultrafast laser systems is a promising issue. In this Letter, a method based on a feed-forward neural network(FNN) model with a simple structure is adopted to inversely predict the full-field supercontinuum generation and recover the initial pulse.The performance of the FNN and its dependence on the predicted pulse features are further explored by a reconstruction test. The generalization ability of the proposed method is further demonstrated in the case with an initial chirp.展开更多
基金This work was supported in part by the National Natural Science Foundation of China 61975021in part by the Science and Technology Project of Jilin Province under Grant 20170414041GHin part by the Research Project of Jilin Provincial Education Department under Grant JJKH20181090KJ.
文摘We integrally demonstrate 2μm mode-locked pulses performances in all-fiber net anomalous dispersion cavity.Stable mode-locking operations with the center wavelength around 1950–1980 nm can be achieved by using the nonlinear polarization rotation structure and properly designing the dispersion management component.Conventional soliton is firstly obtained with a total anomalous dispersion cavity.Due to the contribution of commercial ultra-high numerical aperture fibers,net dispersion is reduced to-0.077 ps2.So that stretched pulse with 19.4 nm optical bandwidth is obtained and the de-chirped pulse-width can reach 312 fs using extra-cavity compression.Under pump power greater than 890 mW,stretched pulse can evolve into noise-like pulse with 41.3 nm bandwidth.The envelope and peak of such broadband pulse can be compressed with up to 2.2 ps and 145 fs,respectively.The single pulse energy of largely chirped stretched and noise-like pulse can reach 1.785 nJ and 1.53 nJ,respectively.Furthermore,extra-cavity compression can also contribute to a significant increase of peak power.
基金Financial support from the program of the National Natural Science Foundation of China (Grant no.52105057,51905222)Natural Science Foundation of Jiangsu Province (Grant no.BK20200916)+3 种基金China Postdoctoral Science Foundation (no.2021M691307,no.2022T150274)Jiangsu Postdoctoral Research Foundation (no.2021K543C)Key Research Project of Zhejiang LabSenior Talent Foundation of Jiangsu University (Grant no.5501110013)are acknowledged.
文摘Coiled polymer artificial muscles with both large tensile stroke and giant force generation are needed for practical applications in robotics,soft exosuits,and prosthesis.However,most polymer yarn artificial muscles cannot generate a large force or stress.Here,we report an inexpensive Twisted and Coiled Polymer artificial muscle(TCP)that performs both large isobaric and isometric contractions.This TCP can generate a tensile stroke of 20.1%and a specific work capacity of up to 1.3 kJ kg^(−1) during temperature changes from 20 to 180℃.Moreover,the nylon yarn artificial muscle produced a reversible output stress of 28.4 MPa,which is 100 times larger than human skeletal muscle.A robot arm and a simple gripper were made to demonstrate the isobaric actuation and isometric actuation of our TCP muscle,repectivley.Thus,the polymer artificial muscles with dual-mode actuation show potential applications in the field of robotics,grippers,and exoskeletons and so on.
基金supported by the National Natural Science Foundation of China (Grant Nos. 62405128, 61827821,62220106006, and 62361136584)the China Postdoctoral Science Foundation (Grant No. 2024M751299)+2 种基金the Shenzhen Science and Technology Program (Grant Nos. SGDX202111-23114001001 and JSGGKOTD20221101115656030)the Guangdong Basic and Applied Basic Research Foundation(Grant No. 2021B1515120013)the Southern University of Science and Technology High Level of Special Funds (Grant Nos. G030230001 and G03034K004)。
文摘Recent years have seen significant advances in the study of dissipative soliton molecules in ultrafast lasers, driven by their remarkable connections to a wide range of physical systems. However, understanding and controlling the underlying physics of soliton molecules remain elusive due to the absence of a universal physical model that adequately describes intramolecular motion. We demonstrate that resonant excitation generates breather soliton molecules, with their resonance susceptibility exhibiting high amplitude-driven operations that can be well understood within the framework of the Duffing model. Harnessing powerful experiment techniques and detailed numerical simulations, we reveal the fundamental resonant mode within intrapulse separation constrained to the 100 fs level as well as the presence of the subharmonic and overtones. Additionally, we observe chaotic dynamics arising from the multiple-frequency nonlinear interactions in a strongly dissipative regime. Our work provides a perspective on the complex interactions of dissipative optical solitons through the lens of nonlinear physics. This approach offers a simple test bed for complex nonlinear physics research, with ultrafine scanning of temporal separations of ultrashort laser pulses demonstrating significant potential for applications requiring high detection sensitivity.
基金supported by the National Natural Science Foundation of China(61975144,61827821,62220106006,and 62361136584)Shenzhen Science and Technology Program(SGDX20211123114001001 and JSGGKQTD 20221101115656030)Guangdong Basic and Applied Basic Research Foundation(2021B1515120013).
文摘Soliton molecules in optical resonators have attracted remarkable attention in nonlinear dynamics,driven by their compelling analogies with matter molecules.So far,while extensive research has been conducted on their generation,pulsations,and dissociation behaviors,the investigation of their quasi-periodic dynamics has been relatively limited.Here,we present a systematic exploration of the quasi-periodic dynamics of soliton molecules using advanced balanced optical cross-correlation techniques.The incommensurable quasi-period bifurcations constituted of cascaded Hopf bifurcations are found,providing an unambiguous pathway toward chaotic soliton molecules.The chaotic intramolecular dynamics are analyzed by time series,radio frequency spectra,phase portraits,and Lyapunov exponent analysis.In addition,we reveal an intrinsic frequency entrainment phenomenon experimentally.Such frequency entrainment provides a novel perspective on synchronization in optical resonators,encompassing the competition and interaction of oscillations across multiple temporal scales.Our experimental findings offer clear proof that the gain dynamics serve as the origin of the binding forces between solitons within the molecule,which are well supported by the numerical simulations.By advancing the understanding of sub-femtosecond resolved quasi-period dynamics of optical soliton molecules,this study contributes to the broader field of complex nonlinear dynamics,paving the way for future explorations into the intricate behaviors of solitons within optical resonators and relevant fields.
基金supported by the National Natural Science Foundation of China(Nos.61827821 and 62227821)。
文摘Pulse duration is considered as one of the most important characteristics of high-power femtosecond lasers.However,pulses output from the laser system are susceptible to ambient changes and manifest the instability of pulse durations in an open environment.In this paper,incorporating the algorithmic framework of the improved stochastic hill-climbing search and incremental proportional-integral controller,temperature-induced fluctuations of pulse duration can be effectively compensated by an automatic feedback control in an all-fiber chirped-pulse amplification system.In the experiment,sub-hundred femtosecond fluctuation of pulse duration is introduced to verify the performance robustness of the proposed pulse-duration feedback control(PDFC).The stability of pulse duration is obviously higher than the case without the feedback control,and the peak-to-peak fluctuation of pulse duration is reduced to 6.5%.Furthermore,the robust switching between different pulse durations proves the versatility of the PDFC.We expect that the proposed feedback control method could provide a novel insight into high-power femtosecond lasers widely applied in fundamental researches and industrial fields.
基金supported by the National Natural Science Foundation of China (Nos.61827821 and 62227821)。
文摘Recently, artificial intelligence has been proven as an effective modeling tool in ultrafast optics;its application in the design of ultrafast laser systems is a promising issue. In this Letter, a method based on a feed-forward neural network(FNN) model with a simple structure is adopted to inversely predict the full-field supercontinuum generation and recover the initial pulse.The performance of the FNN and its dependence on the predicted pulse features are further explored by a reconstruction test. The generalization ability of the proposed method is further demonstrated in the case with an initial chirp.
