Experimental and numerical study of laser energy effect on the thermal lensing behavior of ethyl acetate and ethanol by thermal lens spectroscopy

Abstract

In this study, thermal lensing behavior of ethyl acetate and ethanol was studied based on thermal lens spectroscopy both experimentally and numerically. The simulations were performed using Finite Element Method. At 0.1j laser energy, the fall time of these liquids were measured 1.66 and 1.56 millisecond experimentally. Also, temperature variations due to formation of thermal lensing were obtained in order of millikelvins. Then, thermal lensing parameters at different Nd:YAG laser energies were investigated. Results showed that with increasing laser energy, the fall time decreases and temperature variations increases. In all measurements, experimental and simulation results were in excellent agreement. Finally, to evaluate the accuracy and applicability of our experimental setup and simulation model, the thermal diffusivity of ethanol based on our results was calculated and good agreement with the literature values was observed. Therefore, this setup can be used to measure the thermal diffusivity of unknown samples with high accuracy.