Linear and nonlinear optical absorption of position-dependent mass oscillators

Abstract

We study the linear $(\alpha^{(1)} )$, nonlinear $(\alpha^{(3)})$ and total $(\alpha)$ optical absorptions of position-dependent mass oscillators (PDMOs). We consider three mass distributions $(m(x,\lambda))$ used to describe semiconducting structures; $\lambda$ is a deformation parameter. In the limit $\lambda\rightarrow 0$, the three systems describe electrons in a parabolic quantum well. For the system $m_1(x)=m_0/[1+(\lambda x)^2 ]^2$ we observe that $\alpha^{(1)}(\omega)) (\alpha^{(3)}(\omega))$ increases (decreases) with increasing $\lambda$. For $m_2 (x)=m_0 [1+(\lambda x)^2 ]$ and $m_3(x)=m_0 [1 + tanh^2 (\lambda x) ]$ the opposite occurs. In the light of the PDMO approach we observe the $m_2 (x)$ and $m_3(x)$ systems are very similar, and can not be distinguished by optical transitions between the two lowest electronic levels. We also discussed about the total optical absorption of the systems.