Multiphoton intraband absorption of femtosecond light pulses in crystals: I. General relations

Abstract

We have developed a theory of the transient absorption of femtosecond light pulses by free electrons in the course of intraband transitions involving the participation of phonons. General expressions have been obtained for the probability of transition of an electron from the bottom of the conduction band to a highly excited state due to the absorption of several photons and either the absorption or emission of a phonon.