The Nonlinear Absorption Coefficient of Strong Electromagnetic Waves Caused by Electrons Confined in Quantum Wires

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 (electron-optical 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 oil the intensity E(0) and the frequency Omega of the external strong electromagnetic wave, the temperature T of the system, the radius of the wires R, and the cyclotron frequency omega(c) (for the case of the presence of an external magnetic field) is obtained. The analytic expressions are numerically calculated and discussed for GaAs/GaAsAl quantum wires. The results are compared with those for normal bulk semiconductors and quantum wells to show the differences.