The photon emission spectrum of the hydrogen atoms in an intense high-frequency laser pulse is simulated by using one-dimensional soft Coulomb potential. Regular fine structures appear on the two sides of both the odd...The photon emission spectrum of the hydrogen atoms in an intense high-frequency laser pulse is simulated by using one-dimensional soft Coulomb potential. Regular fine structures appear on the two sides of both the odd and even multiples of photon energy of the laser field besides the ordinary odd harmonic peaks. It is proved that the splits of the fine structures are responsible for hyper-Raman lines and the energy spacing between the odd harmonic lines is equal to the difference in energy between the eigenstates with the same parity of the time averaged Krameters-Henneberger (KH) potential. By analysing the features of the fine structures, we also verify that the so-called even order harmonics under the stabilization condition are indeed hyper-Raman lines caused by the transitions between the dressed atomic states with different values of parity.展开更多
Above-band-gap optical excitation of electron-hole pairs screens the doping-induced surface electric field and generates terahertz(THz)pulses via free-carrier transport.THz emission from a heavily doped silicon surfac...Above-band-gap optical excitation of electron-hole pairs screens the doping-induced surface electric field and generates terahertz(THz)pulses via free-carrier transport.THz emission from a heavily doped silicon surface is much weaker than that of lightly doped samples.A polarity reversal of the THz electric field is observed in heavily doped p-type silicon,indicating that the doping related and carrier induced surface electric fields oppose each other.By comparing the penetration depth of the excitation laser with the thickness of the depletion layer for the doped silicon,it is shown that competition between diffusion and drift current causes the polarity reversal.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 10474138, the National High-Tech ICF Committee in China, and China Research Association of Atomic and Molecular Data.
基金Project supported by the National Natural Science Foundation of China (Grant No 10734140)the National Basic Research Program of China (Grant No 2007CB815105)the National High Technology Research and Development Program for Inertial Confinement Fusion of China
文摘The photon emission spectrum of the hydrogen atoms in an intense high-frequency laser pulse is simulated by using one-dimensional soft Coulomb potential. Regular fine structures appear on the two sides of both the odd and even multiples of photon energy of the laser field besides the ordinary odd harmonic peaks. It is proved that the splits of the fine structures are responsible for hyper-Raman lines and the energy spacing between the odd harmonic lines is equal to the difference in energy between the eigenstates with the same parity of the time averaged Krameters-Henneberger (KH) potential. By analysing the features of the fine structures, we also verify that the so-called even order harmonics under the stabilization condition are indeed hyper-Raman lines caused by the transitions between the dressed atomic states with different values of parity.
基金Project supported by the National Natural Science Foundation of China （Grant No 10474138） and the National High-Tech Inertial Confinement Fusion Committee in China.
基金Supported by the National Key Research and Development Program of China(Grant No.2019YFA0307704)the NSAF Joint Fund(Grant No.U1830206)+1 种基金the Major Research Project of National Natural Science Foundation of China(Grant No.91850201)the National Natural Science Foundation of China(Grant Nos.11974426,11974425,11874425,11774428,and 12074431).
文摘Above-band-gap optical excitation of electron-hole pairs screens the doping-induced surface electric field and generates terahertz(THz)pulses via free-carrier transport.THz emission from a heavily doped silicon surface is much weaker than that of lightly doped samples.A polarity reversal of the THz electric field is observed in heavily doped p-type silicon,indicating that the doping related and carrier induced surface electric fields oppose each other.By comparing the penetration depth of the excitation laser with the thickness of the depletion layer for the doped silicon,it is shown that competition between diffusion and drift current causes the polarity reversal.
