Two-Photon Absorption inCu2O

Abstract

In the first part, a general theoretical treatment of two-photon absorption in semiconductors is presented. It includes excitonic effects in the intermediate as well as final states. $s$ and $p$ excitonic final states are discussed separately. In the second part, the two-photon absorption of ${\mathrm{Cu}}_2$O at 77°K is presented. The spectral region studied includes transitions from the two upper valence bands to the two lower conduction bands. Excitonic structures are observed. The results are discussed within the framework of the theory presented in part one.