Optical intersubband transitions in conduction-band quantum wells

In this work, theoretical formulation for optical intersubband transitions has been developed within the framework of a simple one-band model by including the spatial variation of effective mass in quantum-well heterostructures. It has been shown how the in-plane polarized optical inter-conduction-subband transitions could be made large in direct-band-gap semiconductor quantum wells. However, calculations have confirmed that the normal-to-plane polarized optical intersubband transition is still dominant. The dependence of optical intersubband transitions on quantum-well structure geometry and parameters has been investigated, which provides insights to the underlying physics, and suggests a way how experiments could be carried out to examine these physical phenomena related to optical intersubband transitions.