Due to the promising applications of femtosecond laser filamentation in remote sensing,great demands exist for diagnosing the spatiotemporal dynamics of filamentation.However,until now,the rapid and accurate diagnosis...Due to the promising applications of femtosecond laser filamentation in remote sensing,great demands exist for diagnosing the spatiotemporal dynamics of filamentation.However,until now,the rapid and accurate diagnosis of a femtosecond laser filament remains a severe challenge.Here,a novel filament diagnosing method is proposed,which can measure the longitudinal spatial distribution of the filament by a single laser shot-induced acoustic pulse.The dependences of the point-like plasma acoustic emission on the detection distance and angle are obtained experimentally.The results indicate that the temporal profile of the acoustic wave is independent of the detection distance and detection angle.Using the measured relation among the acoustic emission and the detection distance and angle,a single measurement of the acoustic emission generated by a single laser pulse can diagnose the spatial distribution of the laser filament through the Wiener filter deconvolution(WFD)algorithm.The results obtained by this method are in good agreement with those of traditional point-by-point acoustic diagnosis methods.These findings provide a new solution and idea for the rapid diagnosis of filament,thereby laying a firm foundation for femtosecond laser filament-based promising applications.展开更多
在测量电力系统瞬态过电压时,分压器的响应特性、测量和采样中产生的误差及各种背景噪声的干扰,很容易导致实际测量得到的波形产生畸变,从而影响对波形的观察与分析。为此,提出了一套解决上述问题的方案:先通过对实际测得的波形进行离散...在测量电力系统瞬态过电压时,分压器的响应特性、测量和采样中产生的误差及各种背景噪声的干扰,很容易导致实际测量得到的波形产生畸变,从而影响对波形的观察与分析。为此,提出了一套解决上述问题的方案:先通过对实际测得的波形进行离散Gabor滤波,去除采样误差与背景噪声引入的畸变;再经过Wiener反卷积,消除分压器响应特性引入的畸变,从而较好地还原原波形;最后通过该方案中的波形拟合功能,更直观地得到各种参数,从而更便于分析。对IEC1083-2TDG(Test Data Generator)所产生的波形进行的测试结果证实,该方案具有上述功能,并具有相当的准确性与稳定性。展开更多
基金supported by the National Natural Science Foundation of China(Nos.12074198,12061131010,and 12304381)the Russian Science Foundation(RSF)(No.21-49-00023).
文摘Due to the promising applications of femtosecond laser filamentation in remote sensing,great demands exist for diagnosing the spatiotemporal dynamics of filamentation.However,until now,the rapid and accurate diagnosis of a femtosecond laser filament remains a severe challenge.Here,a novel filament diagnosing method is proposed,which can measure the longitudinal spatial distribution of the filament by a single laser shot-induced acoustic pulse.The dependences of the point-like plasma acoustic emission on the detection distance and angle are obtained experimentally.The results indicate that the temporal profile of the acoustic wave is independent of the detection distance and detection angle.Using the measured relation among the acoustic emission and the detection distance and angle,a single measurement of the acoustic emission generated by a single laser pulse can diagnose the spatial distribution of the laser filament through the Wiener filter deconvolution(WFD)algorithm.The results obtained by this method are in good agreement with those of traditional point-by-point acoustic diagnosis methods.These findings provide a new solution and idea for the rapid diagnosis of filament,thereby laying a firm foundation for femtosecond laser filament-based promising applications.
文摘在测量电力系统瞬态过电压时,分压器的响应特性、测量和采样中产生的误差及各种背景噪声的干扰,很容易导致实际测量得到的波形产生畸变,从而影响对波形的观察与分析。为此,提出了一套解决上述问题的方案:先通过对实际测得的波形进行离散Gabor滤波,去除采样误差与背景噪声引入的畸变;再经过Wiener反卷积,消除分压器响应特性引入的畸变,从而较好地还原原波形;最后通过该方案中的波形拟合功能,更直观地得到各种参数,从而更便于分析。对IEC1083-2TDG(Test Data Generator)所产生的波形进行的测试结果证实,该方案具有上述功能,并具有相当的准确性与稳定性。
基金National Natural Science Foundation of China(30870657,30970775,81101106,61108081)Chinese National Programs for High Technology Research and Development(2009AA02Z413)+2 种基金Tianjin Municipal Government of China(09JCZDJC18200,10JCZDJC17300)Tianjin Natural Science Foundation of China(12JCQNJC09400)Ph.D.Programs Foundation of Ministry of Education of China(20100032120064 and 20110032120069)
