A layer-stripping method is presented for simultaneous inversion of compressional velocity and shear velocity in layered medium from single precritical-incident-angle data of P-P and P-SV plane wave seismogram. A fini...A layer-stripping method is presented for simultaneous inversion of compressional velocity and shear velocity in layered medium from single precritical-incident-angle data of P-P and P-SV plane wave seismogram. A finite bandwidth algorithm is provided and results obviously better than previous research work are obtained by the numerical experiments for band-limited seismogram and synthetic data including noise.展开更多
Terahertz （THz） emission from laser-induced air-plasma is presented. The frequency spectra of THz wave are investigated using an air-biased-coherent-detection method. The frequency spectra are measured under differe...Terahertz （THz） emission from laser-induced air-plasma is presented. The frequency spectra of THz wave are investigated using an air-biased-coherent-detection method. The frequency spectra are measured under different pump-pulse and probe-pulse energies. The frequency pump power and we speculate it caused by collision behavior spectra become narrow with the increasing Meanwhile, the bandwidth of the frequency spectra is broadened by the increasing probe power, which can be explained by pulse compression. Based on this finding, the optimal frequency spectrum of THz can be achieved by regulating the probe and pump beam.展开更多
A compact Er：fiber ring laser operated at a fundamental repetition rate of 325 MHz is reported. Two gain fibers with opposite dispersion are employed to shorten the fiber laser cavity for high repetition rate and sol...A compact Er：fiber ring laser operated at a fundamental repetition rate of 325 MHz is reported. Two gain fibers with opposite dispersion are employed to shorten the fiber laser cavity for high repetition rate and soliton-like pulse generation without losing gain and compactness. The spectral bandwidth of the output pulse is 24 nm and the direct pulse duration is 123 fs without extra-cavity compression, which are values near the transform-Hmited range.展开更多
基金Project supported by the National Natural Science Foundation of China and General Corp. for Oil and Gas and Daqing Oilfield.
文摘A layer-stripping method is presented for simultaneous inversion of compressional velocity and shear velocity in layered medium from single precritical-incident-angle data of P-P and P-SV plane wave seismogram. A finite bandwidth algorithm is provided and results obviously better than previous research work are obtained by the numerical experiments for band-limited seismogram and synthetic data including noise.
基金the National Natural Science Foundation of China(Nos.11374007 and 61377109)the Foundation for the Author of National Excellent Doctoral Dissertation of PR China(No.201237)the Support Program for Outstanding Ph.D.Advisors(No.YB20101000701)
文摘Terahertz （THz） emission from laser-induced air-plasma is presented. The frequency spectra of THz wave are investigated using an air-biased-coherent-detection method. The frequency spectra are measured under different pump-pulse and probe-pulse energies. The frequency pump power and we speculate it caused by collision behavior spectra become narrow with the increasing Meanwhile, the bandwidth of the frequency spectra is broadened by the increasing probe power, which can be explained by pulse compression. Based on this finding, the optimal frequency spectrum of THz can be achieved by regulating the probe and pump beam.
基金supported by the National "973" Program of China (No. 2013CB922400)the National Natural Science Foundation of China (Nos. 60927010,10974006,and 11027404)the Templeton Foundation
文摘A compact Er：fiber ring laser operated at a fundamental repetition rate of 325 MHz is reported. Two gain fibers with opposite dispersion are employed to shorten the fiber laser cavity for high repetition rate and soliton-like pulse generation without losing gain and compactness. The spectral bandwidth of the output pulse is 24 nm and the direct pulse duration is 123 fs without extra-cavity compression, which are values near the transform-Hmited range.
