Поглощение мощного света свободными электронами в кристаллах: внутризонные электрон-фононные осцилляции Раби

Abstract

Absorption of high-intensity visible or near-IR pulsed laser radiation at free electrons in crystals is calculated in the modified resonance approximation. The probabilities $W_{exc}$ of intraband transitions with a change in the electron energy by $\hbar(\omega\pm\omega_l)$, where $\omega$ is the radiation frequency and $/omega_l$ the frequency of longitudinal optical phonons involved in the process, are derived. It is shown that specific electron–phonon Rabi oscillations with the frequency $\Omega_R$ can occur and radiation is absorbed only until the point in time $\tau_1$, at which the first maximum in the dependence $W_{exc} (t)$, where t is the time elapsed from the beginning of the laser pulse, is reached. It is shown that, in the case of prebreakdown radiation intensities, the processes of high orders in field of the radiation wave substantially influence $W_{exc}$, $\tau_1$, and $\Omega_R$.