Investigation of optical properties of choline chloride-lactic acid deep eutectic solvent under continuous wave laser irradiation regime

Abstract

We report on the nonlinear properties of the series of deep eutectic solvents (DESs) which are prepared by a certain ratio of choline chloride as the base and lactic acid as additive materials. The z-scan technique is used to characterize the nonlinear index and absorption of the solvents. Obtained results indicated a negative nonlinear index of the order of about 10−9 cm2/W for the DES solvents at 808 nm of a ∼60-mW CW laser source. It is further found that while the different ratios of lactic acid are increasingly added to the choline chloride, the nonlinear index of solvents are accordingly changed by a factor of 1.2 in magnitude. The results of the open-aperture z-scan confirmed that neither the solvents nor the lactic acid responded to the nonlinear absorption. The represented experiment suggested that with a novel look at these series of DES liquids, it is possible to improve their nonlinear properties by engineering the ratio of choline chloride and lactic acid. © 2024 Elsevier B.V.