  Based on the quantum transport equation for the electron-phonon system, the
absorption coefficient of sound (acoustic phonons) by absorption of laser
radiation in cylindrical quantum wires is calculated for the case of monophoton
absorption process and the case of multiphoton absorption process. Analytical
expressions and conditions for the absorption 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.
