Magnetic field effects on the linear and nonlinear optical properties of coaxial cylindrical quantum well wires

In this work, the influence of an external magnetic field on the refractive index changes and optical absorption coefficients of a typical GaAs/AlxGa1-xAs coaxial cylindrical quantum well wire is studied. Energy eigenvalues and eigenvectors in the presence of a magnetic field are calculated using the fourth-order Runge-Kutta method and optical properties are obtained using the compact density matrix approach. It is found that the resonant peak values of the linear and the third-order nonlinear refractive index changes as well as the optical absorption coefficients of a cylindrical quantum wire decrease with increasing the magnetic field. However, these optical properties of a coaxial cylindrical quantum well wire are nonmonotonic functions of the magnetic field, due to the anticrossing of the subbands. The anticrossing effect leads to a large increase of the resonant peak values of these optical properties. Results also indicate that the resonant peak values of these optical properties decrease with increasing the barrier width. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3694779]