Intersubband Absorption in Coupled Double Quantum Wells Driven by a Strong Terahertz Field

The quasienergy ladders of a symmetric double quantum well driven by a terahertz (THz) field are nonperturbatively calculated within the Floquet theory. The dependence of the quasienergies on the intensity of the driving THz field is discussed. Avoided crossings and crossings of the quasienergies belonging to same and different parity classes are demonstrated. The weights of the THz sidebands of the intersubband transitions are also presented. The weights of the n-th sideband are symmetric between the different sets of the transitions with n positive and negative respectively, while the weights of the n-th sideband are asymmetric between the same sets of the transitions with n positive and n.