Enhancement of thermal lens signal intensity from molecules of rhodamine 6-g dispersed in colloidal silver

Abstract

We report a novel technique to enhance the thermal lens signal intensity by the use of silver nanosol. Thermal lens signal measurements of the laser dye rhodamine 6G dissolved in double distilled water has been carried out using the 532 nm excitation from a Diode pumped solid state (DPSS) laser, both in the presence and absence of silver sol for various concentrations. It has been observed that there is a very noticeable increase in signal intensity when silver nanosol is added to the dye solution. Though the enhancement varies with concentration, it is generally greater than 56 percent. The results presented in this work are of great importance to configuration and optimization of extremely sensitive thermal lens instruments, which is the trend in the development of analytical instruments. We have also carried out the fluorescence quantum yield (Qf) measurements of the dye using the dual beam thermal lens technique for two different pump powers and observed that at higher pump power there is only about 10% reduction in the quantum yield at low concentration in comparison with about 50% reduction at low pump power. At higher concentrations, the percentage reductions are almost identical in both cases.