Linear and nonlinear intersubband optical absorption and refractive index change in asymmetrical semi-exponential quantum wells

► Asymmetrical semi-exponential quantum wells have been proposed. ► The wave function are obtained, by solving modified Bessel equation. ► The energy levels are obtained by numerical method. ► Absorption coefficients are strongly affected by σ, U0 and optical intensity I. ► Refractive index changes are also strongly affected by σ, U0 and I.