Power‐dependent study of the photothermal response of several alcoholic media with femtosecond laser‐induced thermal lens

Abstract

We explore the photothermal response of methanol, ethylene glycol, and glycerol using the femtosecond laser‐induced thermal lens spectroscopy (FTLS) technique. A mode mismatched pump–probe spectroscopic technique was utilized to analyze the influence of localized thermal heating on the photothermal response of solvents. The findings revealed a strong dependence on both the input pump power and the molecular characteristics of the solvents. At significantly high pump power, the excess heat load deposited to the solvent is found to be responsible for the induction of the convection currents in the heat transfer mechanisms. Our results highlight that the influence of pump power on photothermal and thermal lens characteristics is intricately linked to the natural drifting and heat transfer mechanisms of solvent molecules. The molecular motion and existing connective processes were correlated with the molecular characteristics of the samples. The present finding reveals that FTLS is a sensitive probe for comprehending the impact of input laser power, molecular structure, and intermolecular H bonding on the photothermal characteristics and thermo‐optical properties of the alcoholic medium.