Optical manipulation based on fusion spliced all-fiber optical tweezers

We proposed and experimentally validated an all-fiber probe based on the fusion splicing of multiple fibers, designed to capture the cells or microparticles. Introducing the 980 nm laser into the optical fiber and shaping the beam with the probe, which was fabricated by coaxially splicing the no-core fiber (NCF) with the graded-index (GRIN) fiber onto the single-mode fiber (SMF), created a light trap. (We took the first letters of three types of fibers and named it SNG probe.) The focusing effect of the Gaussian beam was tuned by matching the lengths of the NCF and GRIN to achieve optical trapping of particles. We simulated the optical field of the SNG all-fiber optical tweezers (AFOTs) and the dynamic force distribution of microparticles at different positions within the optical field. We also developed a numerical analytical model of the OTs to analyze the effect of fiber length on the capture performance. The output optical field distribution of the SNG AFOTs was experimentally tested, confirming the capability of this fiber tweezer for non-contact and long-distance capture of yeast cells (more than 240 μm). This type of OTs has the potential to advance relevant research in biology and chemistry. © 2024 Society of Photo-Optical Instrumentation Engineers (SPIE).