Experimental and Theoretical Investigations of Beam Deformation Produced by Thermal Lens Effect on a Gaussian Laser Beam in Ethanol

In this paper, influence of thermal lens on propagation of a Gaussian beam through ethanol was investigated experimentally and numerically. The influence of laser power on the thermal lens strength and laser beam characteristics at far field was analyzed. The experimental and numerical results show that a Gaussian laser beam is deformed because of thermal lensing effect. According to these results at enough high laser power a doughnut beam is formed. The deformed beam characteristics i.e. the beam diameter, the size of central dark region of the doughnut beam, and the ratio of peak to valley values were also analyzed. The results show that the numerical and experimental results are in good agreement. The results of this investigation can be very useful for experiments involved to pulse laser ablation in liquid environment (PLAL). © 2020, Springer Science+Business Media, LLC, part of Springer Nature.