  Based on the quantum transport equation for the electron-phonon system, the
absorption coefficient of sound (acoustic phonons) by absorption of a laser
radiation in quantum wires with parabolic potential is calculated for the case
of monophoton absorption and the case of multiphoton absorption. Analytical
expressions and conditions for the absorption coefficient of sound are
obtained. Differences between the two cases of monophoton absorption and of
multiphoton absorption are discussed; numerical computations and plots are
carried out for a GaAs/GaAsAl quantum wire. The results are compared with bulk
semiconductors and quantum wells.
