Interation Of Electrons-photons In THz Laser Pulse Driven

In the solid theoretical of electron and photon interactions, the light intensity involved is weak, so people use Quantum Theory to deal with the interaction of electromagnetic radiation fields with matter, usually look for interaction of the electrons and photons to the perturbation. But in strong laser technology specially terahertz pulsed technology get a breakthrough, and the application of terahertz time-domain spectroscopy.Corresponds to the electric field strength much higher than the Coulomb field strength inside the medium is formed, so that the interaction of electrons and photons can no longer simply as a perturbation calculation. So in this paper, applying the perturbation including solid theory, studies the electronic state density under the terahertz laser pulse driven in two-dimensional electron gas system, studies the most basic physical properties of electrons and photons under the two-dimensional electron gas system.This paper describes the terahertz time-domain spectroscopy, broadband terahertz spectrum is obtained by Fourier transform. At the same time using terahertz pulse shaping technique get the terahertz pulse wave for easy to calculation, as this research object, consider the terahertz pulse changes with time, by solving the system of time-dependent Schrodinger equation, conclud the electron time-dependent wave function of two-dimensional electron gas systems, the Green’s function through the line after the Fourier transform, the electron states of density is deduced. Through systematic study the main theoretical conclusions are as follows:(1) strong THz pulse radiation field driven 2DEG system, the DOS and Fermi energy will be modulated by terahertz pulse frequency and strength and the wide of the radiation field;(2) applying an EM driving field to a 2DEG will result in a decrease in the DOS in the low-energy regime and, consequently, Under the condition of fixed system of electron density, the Fermi energy of system will increase;(3) a stronger effect of the radiation on the DOS and the Fermi energy can be observed at relatively low-frequencies and/or high-intensities where a large energy shift induced by the radiation field is present and the processes of the multiphoton emission and absorption are possible;(4) the processes of optical absorption and emission, including the multiphoton absorption and emission, Will affect the electronic density of states.also, dynamic Franz-Keldysh effect was observed.(5) by varying the frequency and/or strength and the wide of the THz radiation, the electron population in different subbands can be varied.