Two-photon absorption in Cd Ga2 S4 and Cd Ga2 S3.96 Se004 Crystals

Two-photon absorption TPA. measurements have been carried out in the chalcopyrite compounds CdGa2S4, CdGa2S3.96 Se0.04 using single-wavelength excitation by a dye laser with ls581 and 600 nm and pulse duration of 35 ps. Non-linear absorption coefficient for direct interband transitions has been measured in both crystals for EHc and E5 c geometries by the non-linear transmittance method. TPA coefficients were found to be bHs 8.0"0.3.=10y9 cmrW, b5s 1.1"0.2. =10y8 cmrW and b s 8.4"0.7.=10y9 cmrW, b s 1.1"0.2.=10y8 cmrW for CdGa S and CdGa S Se H 5 2 4 2 3.96 0.04 respectively. The experimental results are compared with the existing data for other chalcopyrite compounds. q1999 Published by Elsevier Science B.V. All rights reserved.