Generation of bessel beam by using thermal lens

Bessel beam has been gaining strong attention from various applications. In this study, a new concept for generating zero-order Bessel beams was studied theoretically and experimentally. The principle of the generation of a Bessel-like beam is discussed based on Fourier optics. A preliminary model is proposed that accounts for heat conduction and diffraction effect. Analytical modeling results indicated that Bessel beam can be generated by using a thermal lens and a convergent lens. A simple and flexible method to convert a Gaussian laser beam into a Bessel-like beam with a long and narrow focal line by using a thermal lens effect is demonstrated experimentally. Experimental and calculated results show a good agreement for generation and characteristics of Bessel-like beam. Experimental results also show that the focal depth of the Bessel beam can be controlled by adjusting some parameters in the thermal lens system. The paper concludes with suggestions for further research and potential applications for the work.