Optical properties of a quantum well with Razavy confinement potential: Role of applied external fields

Abstract

In this present work, the effect of applied external fields and well width on the optical absorption and refractive index change coefficient of a GaAs quantum well with Razavy confinement potential is theoretically presented. For this, firstly, the confined subband energy levels of the structure and the envelope wave functions corresponding to these states have been computed using the diagonalization method within the framework of effective mass and parabolic band approximation. Then, by using this information, the coefficients of total – linear plus nonlinear – intersubband optical absorption (TOAC) and relative refractive index changes (RRIC) of the structure are evaluated. The obtained numerical results show that the increase in the magnitude of the applied external fields creates a blue shift in TOAC and RRIC. Also, contrarily to the applied external fields, an increment of the quantum well width have induced a red shift in the TOAC and RRIC. We discuss in detail the variation of the diagonal matrix elements and the energy difference (E2–E1) which are responsible for the change of amplitudes of the calculated coefficients. We believe that the obtained numerical results can be useful in the design and application of the next generation devices used in the optoelectronics field.