The effects of surface acoustic waves on the optical properties of AlGaAs-GaAs quantum-well structures

The effects of a propagating surface acoustic wave (SAW) on the transitions in single- and multiple-quantum-well structures and the change in their absorption and refractive index are presented here. The fundamental difference between the effects of an applied electric field and a propagating SAW are those due to a linear and a nonlinear induced field, respectively. The electron and hole energy eigenvalues and envelope functions of the unperturbed structure are determined. The effect of the SAW-induced strain and electric fields on the confining potential of the quantum-well (QW) structure is then calculated and the energy eigenvalues and envelope functions for this perturbed case are determined. The complex refractive index of the structure is then determined for both the perturbed and unperturbed cases, to give the change in refractive index and the absorption coefficient as a function of SAW wavelength, amplitude, barrier composition, well width, and number of wells. The wavelength (λ_ac) and power of the SAW were found to be important in setting the induced changes in the refractive index