Based on the frequency-to-time mapping relation of the linearly chirped pulse, the temporal phase shift induced by a laser-excited wake in a helium gas jet is measured using a chirped-pulse spectral interferometry wi...Based on the frequency-to-time mapping relation of the linearly chirped pulse, the temporal phase shift induced by a laser-excited wake in a helium gas jet is measured using a chirped-pulse spectral interferometry with ～ 140 fs resolution over a temporal region of I ps in a single shot. In this measurement, the image of the wake is obtained with one-dimensional spatial resolution and temporal resolution limited only by the bandwidth and chirp of the pulse. The ＇bubbles＇ feature of the wake structure, along with multiple wakes excited by the main lobe and the side lobe of a laser focal-spot, is captured simultaneously.展开更多
Using the ellipsoidal cavity model, the quasi-monoenergetic electron output beam in laser-plasma interaction is described. By the cavity regime the quality of electron beam is improved in comparison with those generat...Using the ellipsoidal cavity model, the quasi-monoenergetic electron output beam in laser-plasma interaction is described. By the cavity regime the quality of electron beam is improved in comparison with those generated from other methods such as periodic plasma wave field, spheroidal cavity regime and plasma channel guided acceleration. Trajectory of electron motion is described as hyperbolic, parabolic or elliptic paths. We find that the self-generated electron bunch has a smaller energy width and more effective gain in energy spectrum. Initial condition for the ellipsoidal cavity is determined by laser-plasma parameters. The electron trajectory is influenced by its position, energy and cavity electrostatic potential.展开更多
Up to third-order temporal correction in terms of a small dimensionless temporal parameter ε=1/（ωoto） （ω0=ck0 the central oscillatory frequency, to the pulse duration of half period）, the field expressions of u...Up to third-order temporal correction in terms of a small dimensionless temporal parameter ε=1/（ωoto） （ω0=ck0 the central oscillatory frequency, to the pulse duration of half period）, the field expressions of ultra-short focused laser pulses are explicitly presented. To evaluate the correction efficacy, electric amplitudes of zeroth-order and higher-order corrected fields are compared for different pulse durations. Furthermore, electron interaction with ultra-short laser pulses is simulated using both the zeroth-order and higher-order corrected field equations. Our simulation results show that the third-order correction terms should be considered for investigating the interaction if the laser pulse duration decreases to a few optical periods.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 61377102the Defense Industrial Technology Development Program under Grant No B1520133010
文摘Based on the frequency-to-time mapping relation of the linearly chirped pulse, the temporal phase shift induced by a laser-excited wake in a helium gas jet is measured using a chirped-pulse spectral interferometry with ～ 140 fs resolution over a temporal region of I ps in a single shot. In this measurement, the image of the wake is obtained with one-dimensional spatial resolution and temporal resolution limited only by the bandwidth and chirp of the pulse. The ＇bubbles＇ feature of the wake structure, along with multiple wakes excited by the main lobe and the side lobe of a laser focal-spot, is captured simultaneously.
文摘Using the ellipsoidal cavity model, the quasi-monoenergetic electron output beam in laser-plasma interaction is described. By the cavity regime the quality of electron beam is improved in comparison with those generated from other methods such as periodic plasma wave field, spheroidal cavity regime and plasma channel guided acceleration. Trajectory of electron motion is described as hyperbolic, parabolic or elliptic paths. We find that the self-generated electron bunch has a smaller energy width and more effective gain in energy spectrum. Initial condition for the ellipsoidal cavity is determined by laser-plasma parameters. The electron trajectory is influenced by its position, energy and cavity electrostatic potential.
基金Supported partially by the National Natural Science Foundation of China under Grant Nos 10475018 and 10335030, the National Key Basic Research Special Foundation （NKBRF） of China under Grant No G1999075200, and the Fudan Innovation Foundation for Graduate Student under Grant No CQH5913002.
文摘Up to third-order temporal correction in terms of a small dimensionless temporal parameter ε=1/（ωoto） （ω0=ck0 the central oscillatory frequency, to the pulse duration of half period）, the field expressions of ultra-short focused laser pulses are explicitly presented. To evaluate the correction efficacy, electric amplitudes of zeroth-order and higher-order corrected fields are compared for different pulse durations. Furthermore, electron interaction with ultra-short laser pulses is simulated using both the zeroth-order and higher-order corrected field equations. Our simulation results show that the third-order correction terms should be considered for investigating the interaction if the laser pulse duration decreases to a few optical periods.
