Fluidic laser beam shaper by using thermal lens effect

Laser measurement and laser processing techniques have been gaining strong attention from various applications. This research aims at the development of a fluidic laser beam shaper, and in order to fulfill the objective, thermal lens effect characteristics are studied. This phenomenon has the optical property of a divergent lens since the refractive index distribution on the optical axis is formed when a liquid is irradiated. In this research, effects of the pump power and the propagation distance to the probe beam profile are investigated experimentally and theoretically, with the purpose of developing a fluidic laser beam shaper. It is indicated that, by controlling some parameters in thermal lens system such as the pump power (in the regime of linear optics) and absorption coefficient, an input Gaussian beam can be converted into a flat-top beam profile. The relationship between the distance to obtain the flat-top beam, the pump power and absorption coefficient is investigated to show the flexibility of the fluidic laser beam shaper in many fields of laser application.