Beam intensity shaping with a 3D printed on-fiber microlens

Spatial beam intensity shaping is important in various applications, including laser fabrication and medical treatment. In this study we present a new method for doughnut beam shaping using a 3D nanoprinted on-fiber microlens. The optical structure of the microlens was initially designed and optimized using software based on illumination optics. Subsequently, the microlens was fabricated onto the tip of a single-mode fiber employing the technique of femtosecond laser-induced two-photon polymerization. By using the fiber-tip microlens, both simulation and experimental results have demonstrated the successful transformation of the Gaussian beam emitted from a single-mode fiber into a high-quality doughnut beam. The proposed microlens shows larger tolerance in fabrication resolution compared with optical diffraction beam shaping elements.