Figure 3.

An asymmetric double well as an active element in periodic cascade quantum well structure. ( a) Proposed design of the active element of the periodic cascade quantum well structure and the calculated wave functions of the first and second subbands. ( b) The dependence of the 1 to 2 intersubband spacing on the narrow well width a_R. (c) The values of the averages 〈z〉_ν for corresponding subbands as a function of narrow well width a_R.