We demonstrate that the filamentation process is strongly influenced by the polarization state of the driver laser. When the laser polarization changes from linear to circular, the critical power for the self-focusing...We demonstrate that the filamentation process is strongly influenced by the polarization state of the driver laser. When the laser polarization changes from linear to circular, the critical power for the self-focusing of a Ti：Sapphire laser （800 nm, 40 fs） in air increases from about 9.6 ± 1.0 to 14.9± 1.5 GW, while the second nonlinear refractive index n2 of air decreases from 9.9 × 10-2o to 6.4 ×10-20 cm2/W. We also demonstrate that the luminescence from the neutral nitrogen molecules at 337 nm is dependent on both the laser intensity and plasma density inside the filament.展开更多
The electrical characterization of AlGaN/GaN interface is reported.The dependence of two-dimensional electron gas（2-DEG） density at the interface on the Al mole fraction and thickness of AIGaN layer as well as on th...The electrical characterization of AlGaN/GaN interface is reported.The dependence of two-dimensional electron gas（2-DEG） density at the interface on the Al mole fraction and thickness of AIGaN layer as well as on the thickness of GaN cap layer is presented.This information can be used to design and fabricate AlGaN/GaN based MODFET（modulation doped field effect transistor） for optimum DC and RF characteristics.展开更多
基金supported in part by the National Natural Science Foundation of China(Nos.61625501,61427816,and 61235003)the National Basic Research Program of China(No.2014CB921300)+1 种基金the Open Fund of the State Key Laboratory of High Field Laser Physics(SIOM)the Program for JLU Science and Technology Innovative Research Team(JLUSTIRT)(No.2017TD-21)
文摘We demonstrate that the filamentation process is strongly influenced by the polarization state of the driver laser. When the laser polarization changes from linear to circular, the critical power for the self-focusing of a Ti：Sapphire laser （800 nm, 40 fs） in air increases from about 9.6 ± 1.0 to 14.9± 1.5 GW, while the second nonlinear refractive index n2 of air decreases from 9.9 × 10-2o to 6.4 ×10-20 cm2/W. We also demonstrate that the luminescence from the neutral nitrogen molecules at 337 nm is dependent on both the laser intensity and plasma density inside the filament.
文摘The electrical characterization of AlGaN/GaN interface is reported.The dependence of two-dimensional electron gas（2-DEG） density at the interface on the Al mole fraction and thickness of AIGaN layer as well as on the thickness of GaN cap layer is presented.This information can be used to design and fabricate AlGaN/GaN based MODFET（modulation doped field effect transistor） for optimum DC and RF characteristics.
