The idea of network splitting according to time delay and weight is introduced.Based on the cyber physical systems(CPS),a class of multi-weighted complex transportation networks with multiple delays is modeled.The fin...The idea of network splitting according to time delay and weight is introduced.Based on the cyber physical systems(CPS),a class of multi-weighted complex transportation networks with multiple delays is modeled.The finite-time synchronization of the proposed complex transportation networks model is studied systematically.On the basis of the theory of stability,the technique of adaptive control,aperiodically intermittent control and finite-time control,the aperiodically intermittent adaptive finite-time synchronization controller is designed.The controller designed in this paper is beneficial for understanding the synchronization in multi-weighted complex transportation networks with multiple delays.In addition,the conditions for the existence of finite time synchronization have been discussed in detail.And the specific value of the settling finite time for synchronization is obtained.Moreover,the outer coupling configuration matrices are not required to be irreducible or symmetric.Finally,simulation results of the finite-time synchronization problem are given to illustrate the correctness of the results obtained.展开更多
Laser polarization and its intensity inside a filament core play an important role in filament-based applications.However,polarization dependent clamping intensity inside filaments has been overlooked to interpret the...Laser polarization and its intensity inside a filament core play an important role in filament-based applications.However,polarization dependent clamping intensity inside filaments has been overlooked to interpret the polarization-related filamentation phenomena.Here,we report on experimental and numerical investigations of polarization dependent clamping intensity inside a femtosecond filament in air.By adjusting the initial polarization from linear to circular,the clamping intensity is increased by 1.36 times when using a 30 cm focal length lens for filamentation.The results indicate that clamping intensity inside the filament is sensitive to laser polarization,which has to be considered to fully understand polarizationrelated phenomena.展开更多
We report on a systematic experimental study on the fluorescence spectra produced from a femtosecond laser filament in air under a high electric field. The electric field alone was strong enough to create corona disch...We report on a systematic experimental study on the fluorescence spectra produced from a femtosecond laser filament in air under a high electric field. The electric field alone was strong enough to create corona discharge(CD). Fluorescence spectra from neutral and ionic air molecules were measured and compared with pure high-voltage CD and pure laser filamentation(FIL). Among them, high electric field assisted laser FIL produced nitrogen fluorescence more efficiently than either pure CD or pure FIL processes. The nonlinear enhancement of fluorescence from the interaction of the laser filament and corona discharging electric field resulted in a more efficient ionization along the laser filament zone, which was confirmed by the spectroscopic measurement of both ionization-induced fluorescence and plasma-scattered 800 nm laser pulses. This is believed to be the key precursor process for filament-guided discharge.展开更多
We report on a simultaneous generation of double white light lasers through filamentation by focusing a femtosecond laser pulse. The appearance of the two white light lasers can be controlled by tilting the focusing l...We report on a simultaneous generation of double white light lasers through filamentation by focusing a femtosecond laser pulse. The appearance of the two white light lasers can be controlled by tilting the focusing lens. The spectral bandwidth and the pulse energy of the double white light lasers were controlled by tuning laser filamenting pulse energy and polarization. Two white light lasers with pulse energies of 1.54 m J and 1.84 m J,respectively, were generated with the pump laser energy of 7.43 m J. Besides being beneficial in understanding the multiple white light lasers generation process through multiple filamentation and its control, the results are also valuable for white light laser-based applications.展开更多
Sub-picosecond chirped laser pulse-induced airflow and water condensation were investigated in a cloud chamber.The results indicate that the positively chirped sub-picosecond laser pulses generate a more uniform inten...Sub-picosecond chirped laser pulse-induced airflow and water condensation were investigated in a cloud chamber.The results indicate that the positively chirped sub-picosecond laser pulses generate a more uniform intensity distribution inside the plasma column, leading to a weaker airflow and an elliptic-shaped snow pile. The negatively chirped sub-picosecond laser pulses generate a spark-like intensity distribution inside the plasma column, which produces a wider range of airflow and a round snow pile. The amount of snow weight and the concentration of NO3-- are found to be dependent on the intensity distribution inside the plasma column. The visibly stronger plasma column generates much more snow and a higher concentration of NO3--. These experimental results provide a reference for sub-picosecond laser-induced water condensation in realistic atmospheric conditions.展开更多
We demonstrate a simple technique to filter out the continuum background in filament-induced remote breakdown spectroscopy.By inserting a polarizer before the detector,the continuum background was reduced by more than...We demonstrate a simple technique to filter out the continuum background in filament-induced remote breakdown spectroscopy.By inserting a polarizer before the detector,the continuum background was reduced by more than 42%in filament-induced breakdown spectroscopy at a distance of 3.8 m,while the fluorescence intensity of aluminum atomic lines remains constant.Supercontinuum through self-phase modulation during filamentation mainly contributes to the continuum background.The polarization-gated technique provides a simple way to remove the continuum background in filament-induced remote breakdown spectroscopy.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61803275)Liaoning Provincial Department of Education Scientific Research Fund Project,China(Grant Nos.lnjc202018 and lnzd202007)+1 种基金Liaoning BaiQianWan Talents Program(Grant No.2017076)Liaoning Province Doctor Starting Foundation(Grant No.20170520283).
文摘The idea of network splitting according to time delay and weight is introduced.Based on the cyber physical systems(CPS),a class of multi-weighted complex transportation networks with multiple delays is modeled.The finite-time synchronization of the proposed complex transportation networks model is studied systematically.On the basis of the theory of stability,the technique of adaptive control,aperiodically intermittent control and finite-time control,the aperiodically intermittent adaptive finite-time synchronization controller is designed.The controller designed in this paper is beneficial for understanding the synchronization in multi-weighted complex transportation networks with multiple delays.In addition,the conditions for the existence of finite time synchronization have been discussed in detail.And the specific value of the settling finite time for synchronization is obtained.Moreover,the outer coupling configuration matrices are not required to be irreducible or symmetric.Finally,simulation results of the finite-time synchronization problem are given to illustrate the correctness of the results obtained.
基金supported in part by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB16010400)the International Partnership Program of Chinese Academy of Sciences(Nos.181231KYSB20160045 and 181231KYSB20200033)the support from the Russian Science Foundation(No.2149-00023)。
文摘Laser polarization and its intensity inside a filament core play an important role in filament-based applications.However,polarization dependent clamping intensity inside filaments has been overlooked to interpret the polarization-related filamentation phenomena.Here,we report on experimental and numerical investigations of polarization dependent clamping intensity inside a femtosecond filament in air.By adjusting the initial polarization from linear to circular,the clamping intensity is increased by 1.36 times when using a 30 cm focal length lens for filamentation.The results indicate that clamping intensity inside the filament is sensitive to laser polarization,which has to be considered to fully understand polarizationrelated phenomena.
基金supported in part by National Natural Science Foundation of China (Nos 61221064,11127901 and 11404354)the National 973 Project of China (No.2011CB808103)+2 种基金the Chinese Academy of Sciences and the State Key Laboratory of High Field Laser Physicsthe 100 Talents Program of Chinese Academy of Sciencesthe Shanghai Pujiang Program
文摘We report on a systematic experimental study on the fluorescence spectra produced from a femtosecond laser filament in air under a high electric field. The electric field alone was strong enough to create corona discharge(CD). Fluorescence spectra from neutral and ionic air molecules were measured and compared with pure high-voltage CD and pure laser filamentation(FIL). Among them, high electric field assisted laser FIL produced nitrogen fluorescence more efficiently than either pure CD or pure FIL processes. The nonlinear enhancement of fluorescence from the interaction of the laser filament and corona discharging electric field resulted in a more efficient ionization along the laser filament zone, which was confirmed by the spectroscopic measurement of both ionization-induced fluorescence and plasma-scattered 800 nm laser pulses. This is believed to be the key precursor process for filament-guided discharge.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB16010400)the International Partnership Program of Chinese Academy of Sciences(No.181231KYSB20160045).
文摘We report on a simultaneous generation of double white light lasers through filamentation by focusing a femtosecond laser pulse. The appearance of the two white light lasers can be controlled by tilting the focusing lens. The spectral bandwidth and the pulse energy of the double white light lasers were controlled by tuning laser filamenting pulse energy and polarization. Two white light lasers with pulse energies of 1.54 m J and 1.84 m J,respectively, were generated with the pump laser energy of 7.43 m J. Besides being beneficial in understanding the multiple white light lasers generation process through multiple filamentation and its control, the results are also valuable for white light laser-based applications.
基金supported by the National Natural Science Foundation of China(Nos.11425418,61475167,11404354,and 61221064)the State Key Laboratory Program of the Chinese Ministry of Science and Technology
文摘Sub-picosecond chirped laser pulse-induced airflow and water condensation were investigated in a cloud chamber.The results indicate that the positively chirped sub-picosecond laser pulses generate a more uniform intensity distribution inside the plasma column, leading to a weaker airflow and an elliptic-shaped snow pile. The negatively chirped sub-picosecond laser pulses generate a spark-like intensity distribution inside the plasma column, which produces a wider range of airflow and a round snow pile. The amount of snow weight and the concentration of NO3-- are found to be dependent on the intensity distribution inside the plasma column. The visibly stronger plasma column generates much more snow and a higher concentration of NO3--. These experimental results provide a reference for sub-picosecond laser-induced water condensation in realistic atmospheric conditions.
基金supported in part by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB16000000)the Key Project from Bureau of International Cooperation of Chinese Academy of Sciences(No.181231KYSB20160045)the 100Talents Program of Chinese Academy of Sciences
文摘We demonstrate a simple technique to filter out the continuum background in filament-induced remote breakdown spectroscopy.By inserting a polarizer before the detector,the continuum background was reduced by more than 42%in filament-induced breakdown spectroscopy at a distance of 3.8 m,while the fluorescence intensity of aluminum atomic lines remains constant.Supercontinuum through self-phase modulation during filamentation mainly contributes to the continuum background.The polarization-gated technique provides a simple way to remove the continuum background in filament-induced remote breakdown spectroscopy.
