AbstractCompounds WCu2OS3(PPh3)4 (I) and MoCu2OS3(PPh3)3 (II) were synthesized by reactions of (NH4)2MO2S2 (M = W, Mo), Cu2S and PPh3 in solid state for nonlinear optical studies. A wide transparent window (λ = 400 - 1000 nm) was observed for both clusters, which makes them attractive for nonlinear optical (NLO) applications. NLO properties of the clusters were studied with a 7-ns pulsed laser at 532 nm. Cluster I exhibits mainly optical self-focusing (n2 = 8 × 10-18 m2 W-1, as measured with an 1.2 × 10-4 M acetonitrile solution) with negligibly small nonlinear absorption. Cluster II exhibits both optical self-focusing (n2 = 5 × 10-17 m2 W-1, as measured with a 7.4 × 10-5 M acetonitrile solution) and nonlinear absorption (α2 = 2.6 × 10-10 m W-1). The third-order NLO susceptibilities (χ(3)) of the two clusters at the above-mentioned concentrations are 2 × 10-11 esu for I and 1.2 × 10-10 esu for II respectively. These nonlinear optical properties of the clusters were compared with those of cubic cage shaped and nest shaped clusters to reveal a qualitative structure/NLO property correlation.
Determination of nonlinear absorption (β) and refraction (n2)by the Z-scan method: third-order nonlinear optical properties of π- conjugated Potassium Pentaborate crystal