Experimental study of the third-order optical nonlinearities in Zn1-xAgxSecrystals

The two-photon absorption (TPA) coefficient (beta) and third-order nonlinea r optical susceptibility (chi ((3))) of Zn1-xAgxSe (x = 0.08, 0.10, 0.20) c rystals were investigated using the transmission and degenerate four-wave m ixing methods. The experimental results show that the real and imaginary Da rts of the third-order nonlinear optical susceptibility ( chi ((3))) decrea se with an increase of Ag content. Theoretical simulations of the TPA coefficient (beta) were performed using pseudopotential band energy structure calculations. We have evaluated that for an Ag content of about 4.5% beta achieves its maximum. A good agreement between theoretically calculated and experimentally measured susceptibilit ies is achieved.