Nondegenerate two-photon absorption in ZnSe: Experiment and theory

We experimentally and theoretically investigate the nondegenerate two-photon absorption coefficient beta(omega(1), omega(2)) in the prototypical semiconductor ZnSe. In particular, we provide a comprehensive data set on the dependence of beta(omega(1), omega(2)) on the nondegeneracy parameter omega(1)/omega(2) with the total frequency sum omega(1) + omega(2) kept constant. We find a substantial increase in the two-photon absorption strength with increasing omega(1)/omega(2). In addition, different crystallographic orientations and polarization configurations are investigated. The nonlinear optical response is analyzed theoretically by evaluating the multiband semiconductor Bloch equations including inter- and intraband excitations in the length gauge. The band structure and the matrix elements are taken as an eight-band k.p model. The simulation results are in very good agreement with the experiment.

Automated summary

The study investigates the nondegenerate two-photon absorption coefficient beta(omega(1), omega(2)) in the semiconductor ZnSe, showing a substantial increase in absorption strength with higher omega(1)/omega(2) ratio. Different crystallographic orientations and polarization configurations are considered, with theoretical analysis aligning well with experimental results.