Laser induced photoluminescence from Ge28Se60Sb12 chalcogenide nano colloids

We report the observation of two-photon induced photoluminescence from Ge28Se60Sb12 nano colloid solutions using frequency doubled Nd:YAG laser. Quadratic emission intensity dependence verifies the two photon absorption for the observed luminescence at an excitation of 532 nm. The optical band gap of the material is found to be tunable depending on the cluster size of the nano colloids. The cluster formation and the dependence of the cluster size with concentration were confirmed by the SEM analysis. Confocal imaging was done to confirm the emission from the clusters in the nano colloid solutions.