Un-hydrogenated Diamond-like Carbon （DLC） films were prepared by pulsed laser deposition technique at different substrate temperature. The Raman spectra, the absorption and the photoluminescence spectra were measure...Un-hydrogenated Diamond-like Carbon （DLC） films were prepared by pulsed laser deposition technique at different substrate temperature. The Raman spectra, the absorption and the photoluminescence spectra were measured. The dependence of structure and phetoluminescence properties on deposition temperature were studied in detail. The experimental results indicate that the sp^2 sites form small clus ters that consist of both olefinic chains and aromatic ring groups within the sp^3 matrix. With raising deposition temperature,the optical band gaps increase from 1.87 to 2.85 eV. The main band of photoluminescence centered at around 700nm shifts to short wavelength, and the intensity of this band increases. The photoluminescence can be attributed to carrier localization within an increasing sp^2 clusters. It was clarified that the DLC films are ordered with increasing deposition temperature.展开更多
A （3＋1 ）-dimensional Kadomtse-Petviashvili （KP） equation for nonlinearly interacting intense laser pulses with an electron-positron （e-p） plasma is derived. Taking into account the combined action of the relati...A （3＋1 ）-dimensional Kadomtse-Petviashvili （KP） equation for nonlinearly interacting intense laser pulses with an electron-positron （e-p） plasma is derived. Taking into account the combined action of the relativistic particle mass increase and the relativistic light ponderomotive force, using the perturbation method, and allowing different types solution, we discuss the analytical solution of （3＋1）-dimensional KP-I equation, and give the approximate solutions of vector potential of the intense laser pulse in e-p plasma. Our results may be significantly useful in understanding the nonlinear wave propagation and interaction of intense laser beams in an e-p plasma.展开更多
Interactions of two counter-streaming plasmas driven by high power laser pulses are studied on Shenguang II laser facility.Filamentary structures were observed in the interaction region after the electrostatic shockwa...Interactions of two counter-streaming plasmas driven by high power laser pulses are studied on Shenguang II laser facility.Filamentary structures were observed in the interaction region after the electrostatic shockwave decay.Theoretical analysis and observations indicate that the filaments are because of collisionless mechanisms,which are caused by the electromagnetic instability,such as the beam-Weibel instability.Collision experiments were also carried out for comparison and no filaments were generated.展开更多
文摘Un-hydrogenated Diamond-like Carbon （DLC） films were prepared by pulsed laser deposition technique at different substrate temperature. The Raman spectra, the absorption and the photoluminescence spectra were measured. The dependence of structure and phetoluminescence properties on deposition temperature were studied in detail. The experimental results indicate that the sp^2 sites form small clus ters that consist of both olefinic chains and aromatic ring groups within the sp^3 matrix. With raising deposition temperature,the optical band gaps increase from 1.87 to 2.85 eV. The main band of photoluminescence centered at around 700nm shifts to short wavelength, and the intensity of this band increases. The photoluminescence can be attributed to carrier localization within an increasing sp^2 clusters. It was clarified that the DLC films are ordered with increasing deposition temperature.
基金supported by the National Natural Science Foundation of China (Grant No.10575082)the Natural Science Foundation of Gansu Province under Grant No.3ZS061-A25-014the Natural Science Foundation of Northwest Normal University under Grant No.NWNU-KJCXGC-03-17
文摘A （3＋1 ）-dimensional Kadomtse-Petviashvili （KP） equation for nonlinearly interacting intense laser pulses with an electron-positron （e-p） plasma is derived. Taking into account the combined action of the relativistic particle mass increase and the relativistic light ponderomotive force, using the perturbation method, and allowing different types solution, we discuss the analytical solution of （3＋1）-dimensional KP-I equation, and give the approximate solutions of vector potential of the intense laser pulse in e-p plasma. Our results may be significantly useful in understanding the nonlinear wave propagation and interaction of intense laser beams in an e-p plasma.
基金supported by the National Natural Science Foundation of China(Grant Nos.11135012,10925421,11375262 and 11220101002)the National Basic Research Program of China(Grant No.2013CBA01501)
文摘Interactions of two counter-streaming plasmas driven by high power laser pulses are studied on Shenguang II laser facility.Filamentary structures were observed in the interaction region after the electrostatic shockwave decay.Theoretical analysis and observations indicate that the filaments are because of collisionless mechanisms,which are caused by the electromagnetic instability,such as the beam-Weibel instability.Collision experiments were also carried out for comparison and no filaments were generated.
