Improved photopolymerization for fabricating fiber optical tweezers

In recent years, it has been a new topic to fabricate fiber optical tweezers probes by using photopolymers. However, this method requires coupling the laser into the fiber through a spatial optical path with strict laser and experimental environment requirements. It significantly limits the application scope of optical tweezers. This paper proposes and demonstrates an improved photopolymerization method to fabricate fiber optical tweezers based on an all-fiber structure, improve the fabrication process, and solve the above problems. We configure the all-fiber structure by coaxial welding a single-mode fiber and a multimode fiber to excite a Bessel-like beam. The power density distribution of the Bessel-like beam is advantageous for forming the photopolymerization tip that makes the output beam highly convergent. The fabrication method of the proposed fiber optical tweezers is economical and straightforward. Moreover, it provides a new way of improving the photopolymerization process.