Focusing property and optical field modulation of three-core fiber optical tweezers

Abstract

This work develops a three-core fiber optical tweezers probe with a double cone angle and a tip microlens based on the Lorentz-Mie scattering theory. The primary parameters of the structural probe, such as the cone angle and the thickness of the microlens, are investigated and clarified by theoretical research, model construction, and simulation analysis. The best capture ability is at 44° of second-order cone angle. In order to create a focused light field, the microlens must be thicker than 8 μm. Under the probe framework, we investigated the primary purposes of various core optical powers. We designed a set of optical fiber tweezers control schemes to adjust the capture effect in real time, which enhances the control capability of optical fiber tweezers. We leverage the difference in input optical power between different cores. The focusing effect of the optical field can be changed, enabling real-time control of the captured item, by modifying the incidence angle and power. The power is inversely correlated with the movement of the capture position. The capture point moves 0.1 μm when the optical power is changed to 0.3 W/m.