Analytic expressions for the nonlinear absorption coefficient of a strong electromagnetic wave
caused by electrons confined in cylindrical quantum wires are calculated by using the quantum kinetic
equation for electrons. The problem is considered for electron-phonon scattering mechanisms (electronoptical
phonon scattering and electron-acoustic phonon scattering) in the absence of an external magnetic
field and for electron-optical phonon scattering in the presence of an external magnetic field. The
dependence of the nonlinear absorption coefficient on the intensity E0 and the frequency ?? of the external
strong electromagnetic wave, the temperature T of the system, the radius of the wires R, and the cyclotron
frequency we (for the case of the presence of an external magnetic field) is obtained. The analytic
expressions are numerically calculated and discussed for GaAs/GaAs Al quantum wires. The results are
compared with those for normal bulk semiconductors and quantum wells to show the differences.
