Effect of a terahertz laser field on the electron-DOS in a GaAs/AlGaAs cylindrical quantum wire: finite well model

The influence of a linearly polarized terahertz laser field on the density of states (DOS) for carriers confined in a cylindrical semiconductor quantum wire is investigated here within a nonperturbative scheme, based on the Green's function approach introduced by Xu (1997 Semicond. Sci. Technol. 12 1559). In our finite potential well model, the functional dependence of the DOS on energy is significantly modified by a monochromatic, nonresonant, intense laser radiation polarized along the wire axis. Apart from a uniform blueshift with respect to the laser-free DOS, which is proportional to the laser intensity and to the inverse of the square of the frequency, a remarkable reduction of the DOS, followed by pronounced Franz–Keldysh-like oscillations above the bottom of each 1D sub-band, is obtained. The period of these oscillations is seen to depend more on the laser frequency than on the intensity. Interestingly, with an increase of the laser intensity and/or a reduction of the laser frequency, the DOS profile changes from the usual shape found in 1D electronic systems to a series of discrete peaks similar to that found in quasi-0D systems, such as quantum dots.

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